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Selenium (Python): How to insert value on a hidden input?
Question: I'm using Selenium's WebDriver and coding in Python.
There's a hidden input field in which I'm trying to insert a specific date
value. The field originally produces a calendar, from which a user can select
an appropriate date, but that seems like a more complicated endeavour to
emulate than inserting the appropriate date value directly.
The page's source code looks like this:
<div class="dijitReset dijitInputField">
<input id="form_date_DateTextBox_0" class="dijitReset" type="text" autocomplete="off" dojoattachpoint="textbox,focusNode" tabindex="0" aria-required="true"/>
<input type="hidden" value="2013-11-26" sliceindex="0"/>
where `value="2013-11-26"` is the field I'm trying to inject a value (it's
originally empty, ie: `value=""`.
I understand that WebDriver is not able to insert a value into a hidden input,
because regular users would not be able to do that in a browser, but a
workaround is to use Javascript. Unfortunately that's a language I'm not
familiar with. Would anyone know what would work?
Answer: You can use [`WebDriver.execute_script`](https://selenium-
python.readthedocs.org/en/latest/api.html?highlight=execute_script#selenium.webdriver.remote.webdriver.WebDriver.execute_script).
For example:
from selenium import webdriver
driver = webdriver.Firefox()
driver.get('http://jsfiddle.net/falsetru/mLGnB/show/')
elem = driver.find_element_by_css_selector('div.dijitReset>input[type=hidden]')
driver.execute_script('''
var elem = arguments[0];
var value = arguments[1];
elem.value = value;
''', elem, '2013-11-26')
* * *
**UPDATE**
from selenium import webdriver
driver = webdriver.Firefox()
driver.get('http://matrix.itasoftware.com/')
elem = driver.find_element_by_xpath(
'.//input[@id="ita_form_date_DateTextBox_0"]'
'/following-sibling::input[@type="hidden"]')
value = driver.execute_script('return arguments[0].value;', elem)
print("Before update, hidden input value = {}".format(value))
driver.execute_script('''
var elem = arguments[0];
var value = arguments[1];
elem.value = value;
''', elem, '2013-11-26')
value = driver.execute_script('return arguments[0].value;', elem)
print("After update, hidden input value = {}".format(value))
|
Retrieving comments using python libclang
Question: In the following header file I'd like to get the corresponding `+reflect`
comment to the class and member variable:
#ifndef __HEADER_FOO
#define __HEADER_FOO
//+reflect
class Foo
{
public:
private:
int m_int; //+reflect
};
#endif
Using the python bindings for libclang and the following script:
import sys
import clang.cindex
def dumpnode(node, indent):
print ' ' * indent, node.kind, node.spelling
for i in node.get_children():
dumpnode(i, indent+2)
def main():
index = clang.cindex.Index.create()
tu = index.parse(sys.argv[1], args=['-x', 'c++'])
dumpnode(tu.cursor, 0)
if __name__ == '__main__':
main()
Gives me this output:
CursorKind.TRANSLATION_UNIT None
CursorKind.TYPEDEF_DECL __builtin_va_list
CursorKind.CLASS_DECL type_info
CursorKind.CLASS_DECL Foo
CursorKind.CXX_ACCESS_SPEC_DECL
CursorKind.CXX_ACCESS_SPEC_DECL
CursorKind.FIELD_DECL m_int
The problem is that the comments are missing. Are they stripped by the
preprocessor? Is there any way to prevent that?
Answer: You need to modify the cindex.py script and expose the following function.
class Cursor(Structure):
def getRawComment(self):
return conf.lib.clang_Cursor_getRawCommentText(self)
also add this to the correct spot in cindex.py
("clang_Cursor_getRawCommentText",
[Cursor],
_CXString,
_CXString.from_result),
I had to make my comments using
/*!
* +reflect
*/ though
|
What does the `as` command do in Python 3.x?
Question: I've seen it many times but never understood what the `as` command does in
Python 3.x. Can you explain it in plain English?
Answer: It's not a command per se, it's a keyword used as part of the [`with`
statement](http://docs.python.org/2/reference/compound_stmts.html#the-with-
statement):
with open("myfile.txt") as f:
text = f.read()
The object after `as` gets assigned the result of the expression handled by
the `with` context manager.
Another use is to rename an imported module:
import numpy as np
so you can use the name `np` instead of `numpy` from now on.
The third use is to give you access to an `Exception` object:
try:
f = open("foo")
except IOError as exc:
# Now you can access the Exception for more detailed analysis
|
How to pull info from a string and output it?
Question: I have to create a game where the computer picks a random word and the player
has to guess that word. The computer tells the player how many letters are in
the word. Then the player gets five chances to ask if a letter is in the word.
The computer can only respond with `"yes"` or `"no"`. Then, the player must
guess the word. I only have:
import random
WORDS = ("python", "jumble", "easy", "difficult", "answer", "xylophone", "truck" , "doom" , "mayonase" ,"flying" ,"magic" ,"mine" ,"bugle")
word = random.choice(WORDS)
print(len(word))
correct = word
guess = input("\nYour guess: ")
if guess != correct and guess != "" :
print("No.")
if guess == correct:
print("Yes!\n")
I have no idea how to do this problem.
Answer: I assume you want to let the user ask the computer if a letter is in the word,
5 times. If so, here is the code:
for i in range(5): #Let the player ask 5 times
letter = input("What letter do you want to ask about? ")[0]
#take only the 1st letter if they try to cheat
if letter in correct:
print("yes, letter is in word\n")
else:
print("no, letter is not in word")
The key is the `in` operator within the `for` loop.
|
Can literals in Python be overridden?
Question: Couldn't find a way to phrase the title better, feel free to correct.
I'm pretty new to Python, currently experimenting with the language.. I've
noticed that all built-ins types cannot be extended with other members.. I'd
like for example to add an `each` method to the `list` type, but that would be
impossible. I realize that it's designed that way for efficiency reasons, and
that most of the built-ins types are implemented in C.
Well, one why I found to override this behavior is be defining a new class,
which extends `list` but otherwise does nothing. Then I can assign the
variable `list` to that new class, and each time I would like to instantiate a
new list, I'd use the `list` constructor, like it would have been used to
create the original `list` type.
class MyList(list):
def each(self, func):
for item in self:
func(item)
list = MyList
my_list = list((1,2,3,4))
my_list.each(lambda x: print(x))
Output:
1
2
3
4
The idea can be generalize of course by defining a method that gets a built it
type and returns a class that extends that type. Further more, the original
`list` variable can be saved in another variable to keep an access to it.
Only problem I'm facing right now, is that when you instantiate a `list` by
its literal form, (i.e. `[1,2,3,4]`), it will still use the original list
constructor (or does it?). Is there a way to override this behavior? If the
answer is no, do you know of some other way of enabling the user to extend the
built-ins types? (just like javascript allows extending built-ins prototypes).
I find this limitation of built-ins (being unable to add members to them) one
of Python's drawbacks, making it inconsistent with other user-defined types...
Overall I really love the language, and I really don't understand why this
limitation is REALLY necessary.
Answer: This is a conscientious choice from Python.
Firstly, with regards to patching inbuilt type, this is primarily a design
_decision_ and only secondarily an optimization. I have learnt from much
lurking on the Python Mailing List that monkey patching on builtin types,
although enjoyable for small scripts, serves no good purpose in anything
larger.
Libraries, for one, make certain assumptions about types. If it were
encouraged to extend default types, many libraries would end up fighting each
other. It would also discourage _making_ new types – a deque is a deque, an
ordered set is an ordered set, a dictionary is a dictionary and that should be
that.
Literal syntax is a particularly important point. If you cannot guarantee that
`[1, 2, 3]` is a list, what can you guarantee? If people could change those
behaviours it would have such global impacts as to destroy the stability of a
lot of code. There is a reason _goto_ and global variables are discouraged.
* * *
There is one particular hack that I _am_ fond of, though. When you see
`r"hello"`, this seems to be an extended literal form.
So why not `r[1, 2, 3]`?
class ListPrefixer:
def __init__(self, typ):
self.typ = typ
def __getitem__(self, args):
return self.typ(args)
class MyList(list):
def each(self, func):
return MyList(func(x) for x in self)
e = ListPrefixer(MyList)
e[1, 2, 3, 4].each(lambda x: x**2)
#>>> [1, 4, 9, 16]
* * *
Finally, if you really want to do deep AST hacks, check out
[MacroPy](https://github.com/lihaoyi/macropy).
|
Finding the mode and frequency of items in a Python list
Question: How would you find the mode and frequency of items in a Python list?
This is what I have so for:
elif user_option == 7:
for score in scores_list:
count = scores_list.count(score)
print ("mode(s), occuring" + str(count) + ":")
print(score)
What I need to do is print out the scores that appear the most if the user
inputs a set of scores where 2 appear at the same amount of time and I also
have to display the actual score. But this is what I get when I test it:
Select an option above:7
mode(s), occuring2:
45.0
mode(s), occuring2:
45.0
mode(s), occuring1:
67.0
Answer: if you are trying to count frequency of an item of a list try this:
from collections import Counter
data = Counter(your_list_in_here)
data.most_common() # Returns all unique items and their counts
data.most_common(1) # Returns the highest occurring item
|
How to load data in Python for which data is stored as a customized class
Question: I have a question with loading data in Python.
Basically, I defined all Classes I need in a file called "utility.py". and I
have one data file "result.data" which stores results in form of a specific
class called "Solution" which is defined in "utility.py". What I want to do is
to load "result.data" in another py. file (ex:new.py). From what I know,
cPickle module is the one that can be used. So in new.py, I wrote "from
utility import *", and "Sol=cPickle.load(open('Result.data'))". This works
fine when I worked among windows based system. However, when I tried to load
the result.data I generated in windows system to new.py file in linux or mac
system, The error "ImportError: No module named utility" always occurs.
I'm a not a professional programmer, and I just start to code in python. Could
you please give some guide on how to solve this problem? Thank you in advance.
Answer: Check `sys.path`. Does it contain the location where utility.py is kept? Does
it have current directory ( an empty string )?
That could be the issue.
|
Can pip (or setuptools, distribute etc...) list the license used by each installed package?
Question: I'm trying to audit a Python project with a large number of dependencies and
while I can manually look up each project's homepage/license terms, it seems
like most OSS packages should already contain the license name and version in
their metadata.
Unfortunately I can't find any options in pip or easy_install to list more
than the package name and installed version (via pip freeze).
Does anyone have pointers to a tool to list license metadata for Python
packages?
Answer: You can use `pkg_resources`:
import pkg_resources
def get_pkg_license(pkgname):
"""
Given a package reference (as from requirements.txt),
return license listed in package metadata.
NOTE: This function does no error checking and is for
demonstration purposes only.
"""
pkgs = pkg_resources.require(pkgname)
pkg = pkgs[0]
for line in pkg.get_metadata_lines('PKG-INFO'):
(k, v) = line.split(': ', 1)
if k == "License":
return v
return None
Example use:
>>> get_pkg_license('mercurial')
'GNU GPLv2+'
>>> get_pkg_license('pytz')
'MIT'
>>> get_pkg_license('django')
'UNKNOWN'
|
Error: [only length-1 arrays can be converted to Python scalars] when changing variable order
Question: Dear Stackoverflow Community,
I am very new to Python and to programming in general, so please don't get mad
when I don't get your answers and ask again.
I am trying to fit a curve to experimental data with
scipy.optimization.curve_fit. This is my code:
%matplotlib inline
import matplotlib.pyplot as plt
import numpy as nm
from __future__ import division
import cantera as ct
from matplotlib.backends.backend_pdf import PdfPages
import math as ma
import scipy.optimize as so
R = 8.314
T = nm.array([700, 900, 1100, 1300, 1400, 1500, 1600, 1700])
k = nm.array([289, 25695, 763059, 6358040, 14623536, 30098925, 56605969, 98832907])
def func(A, E, T):
return A*ma.exp(-E/(R*T))
popt, pcov = so.curve_fit(func, T, k)
Now this code works for me, but if I change the function to:
def func(T, A, E)
and keep the rest I get:
TypeError: only length-1 arrays can be converted to Python scalars
Also I am not really convinced by the Parameter solution of the first one. Can
anyone tell me what happens when you change the variable order?
Answer: I wonder whether you data shows an exponential decay of rate. The mathematical
model may not be the most suitable one.
See the doc
string of `curve_fit`
> f : callable The model function, f(x, ...). It must take the independent
> variable as the first argument and the parameters to fit as separate
> remaining arguments.
since your formula is essentially: `k=A*ma.exp(-E/(R*T))`, the right order of
parameters in `func` should be `(T, A, E)` or `(T, E, A)`.
Regarding the order of `A` and `E`, they don't really matter. If you flip
them, the result will get flipped as well:
>>> def func(T, A, E):
return A*ma.exp(-E/(R*T))
>>> so.curve_fit(func, T, k)
(array([ 8.21449078e+00, -5.86499656e+04]), array([[ 6.07720215e+09, 4.31864058e+12],
[ 4.31864058e+12, 3.07102992e+15]]))
>>> def func(T, E, A):
return A*ma.exp(-E/(R*T))
>>> so.curve_fit(func, T, k)
(array([ -5.86499656e+04, 8.21449078e+00]), array([[ 3.07102992e+15, 4.31864058e+12],
[ 4.31864058e+12, 6.07720215e+09]]))
I didn't get your `typeerror` at all.
|
What does [^.]* mean in regular expression?
Question: I'm trying to get 482.75 from the following text: `<span
id="yfs_l84_aapl">482.75</span>`
The regex I used is: `regex = '<span id="yfs_l84_[^.]*">(.+?)</span>'` and it
worked.
But the thing that I do not understand is why [^.]* can match aapl here? My
understanding is that . means any character except a newline; and ^ means
negator. So [^.] should be newline and [^.]* should be any number of new
lines. However this theory is contrary to real world implementation.
Any help is appreciated and thanks in advance.
* * *
The python code I used:
import urllib
import re
htmlfile = urllib.urlopen("http://finance.yahoo.com/q?s=AAPL&ql=0")
htmltext = htmlfile.read()
regex = '<span id="yfs_l84_[^.]*">(.+?)</span>'
pattern = re.compile(regex)
price = re.findall(pattern, htmltext)
print "the price of of aapl is", price[0]
Answer: Within the `[]` the `.` means just a dot. And the leading `^` means "anything
but ...".
So `[^.]*` matches zero or more non-dots.
|
Call oracle stored procedure with cursor output parameter from python script
Question: I am trying to call a oracle stored procedure with 2 in and 1 out parameter
from python script. The problem I am having is passing a cursor out-parameter.
The Oracle stored procedure is essentially:
PROCEDURE ci_lac_state
(LAC_ID_IN IN VARCHAR2,
CI_ID_IN IN VARCHAR2 DEFAULT NULL,
CGI_ID OUT SYS_REFCURSOR)
AS
BEGIN
OPEN cgi_id FOR
...
END;
The python code calling to the database is:
#! /usr/bin/python
import cx_Oracle
lac='11508'
ci='9312'
try:
my_connection=cx_Oracle.Connection('login/passwd@db_name')
except cx_Oracle.DatabaseError,info:
print "Logon Error:",info
sys.exit()
my_cursor=my_connection.cursor()
cur_var=my_cursor.var(cx_Oracle.CURSOR)
my_cursor.callproc("cgi_info.ci_lac_state", [lac, ci, cur_var])
print cur_var.getvalue()
And I get such cursor value as the result:
<__builtin__.OracleCursor on <cx_Oracle.Connection to login@db_name>>
What am I doing wrong?
Thanks.
Answer: I've just had similar issue. `cur_var` has type `<type 'cx_Oracle.CURSOR'>`
and `cur_var.getvalue()` gets object of type `<type 'OracleCursor'>`. To get
data you have to fetched them from the OracleCursor object. Try for example:
print cur_var.getvalue().fetchall()
To see more function of OracleCursor object just check its directory:
dir(cur_var.getvalue())
Hope this will help you!
|
Launching a cmd window with commands using python script?
Question: How do I launch a cmd window and input the commands i specify into the cmd for
windows using a python script?
For example , the script will launch the cmd and input the following : runas
/username:Admin control
Then cmd will then prompt the user for their passwords and open the control
panel. Any idea? Thanks
Answer:
import subprocess
subprocess.call(['runas', '/username:Admin', 'control'])
Don't have a python shell here to test, but this should get you pretty close
to what you want.
It should run the `runas` command which will prompt you for the password, then
launch the control panel. This could easily be done with a batch program too,
or even just a shortcut. Just putting that out there.
* * *
### controlpanel.bat
This one is most comparable to your python script, but it skips having to load
the pyton interpreter.
runas /username:Admin control
* * *
### shortcut
This one lets you have a little more control over the command, and who is
running it. *right click desktop
*new
*shortcut
*Enter "runas /username:Admin control" for the Location.
*Type a name for the shortcut.
* * *
### alternative shortcut
This one is useful if you just want UAC to handle it.
* same as above, but for location type just "control"
* then right click on the new shortcut, and click properties.
* click the shortcut tab
* click "advanced"
* check the "run as administrator" box.
* * *
### Bonus alternative
This gives you a master list of all settings you can change, rather than just
the control panel.
* Create a new folder, and rename it to:
Settings.{ED7BA470-8E54-465E-825C-99712043E01C}
* You can change the "Settings" part to anything you want
* follow the instructions above for "alternative shortcut"
|
Prevent CSS/other resource download in PhantomJS/Selenium driven by Python
Question: I'm trying to speed up Selenium/PhantomJS webscraper in Python by preventing
download of CSS/other resources. All I need to download is img src and alt
tags. I've found this code:
page.onResourceRequested = function(requestData, request) {
if ((/http:\/\/.+?\.css/gi).test(requestData['url']) || requestData['Content-Type'] == 'text/css') {
console.log('The url of the request is matching. Aborting: ' + requestData['url']);
request.abort();
}
};
via: [how can I control phantomjs to skip download some kind of
resource](http://stackoverflow.com/questions/9486377/how-can-i-control-
phantomjs-to-skip-download-some-kind-of-resource)
_How/where can I implement this code in Selenium driven by Python? Or, is
there another better way to stop CSS/other resources from downloading?_
Note: I've already found how to prevent image download by editing service_args
variable via:
[How do I set a proxy for phantomjs/ghostdriver in python
webdriver?](http://stackoverflow.com/questions/14699718/how-do-i-set-a-proxy-
for-phantomjs-ghostdriver-in-python-webdriver?lq=1)
and
[PhantomJS 1.8 with Selenium on python. How to block
images?](http://stackoverflow.com/questions/15371495/phantomjs-1-8-with-
selenium-on-python-how-to-block-images?lq=1)
But service_args can't help me with resources like CSS. Thanks!
Answer: A bold young soul by the name of “watsonmw” [recently
added](https://github.com/detro/ghostdriver/commit/d9b65ed014ed9ff8a5e852cc40e59a0fd66d0cf1)
functionality to Ghostdriver (which Phantom.js uses to interface with
Selenium) that allows access to [Phantom.js API calls which require a page
object](http://phantomjs.org/api/webpage/), like the `onResourceRequested` one
you cited.
For a solution at all costs, consider building from source (which developers
note “takes roughly 30 minutes ... with 4 parallel compile jobs on a modern
machine”) and integrating his patch, linked above.
Then this (untested) Python code should work as a proof of concept:
from selenium import webdriver
driver = webdriver.PhantomJS('phantomjs')
# hack while the python interface lags
driver.command_executor._commands['executePhantomScript'] = ('POST', '/session/$sessionId/phantom/execute')
driver.execute('executePhantomScript', {'script': '''
page.onResourceRequested = function(requestData, request) {
// ...
}
''', 'args': []})
Until then, you’ll just get a `Can't find variable: page` exception.
Good luck! There are a lot of great alternatives, like working in a Javascript
environment, driving Gecko, proxies, etc.
|
Python Decorator Self-firing
Question: I am fairly new to Python and have been learning about decorators. After
messing around with Flask, I am trying to write some code that simulates their
route handler/decorators, just to understand how decorators (with arguments)
work.
In the code below, the route decorator seems to call itself once the script
runs. My question is, how is it possible that `app.route()` gets called when i
run this script, and what is really happening here? Notice i don't call my
`index()` function anywhere directly.
# test.py
class Flask(object):
def __init__(self, name):
self.scriptname = name
def route(self, *rargs, **kargs):
args = list(rargs)
if kargs:
print(kargs['methods'])
def decorator(f):
f(args[0])
return decorator
app = Flask(__name__)
@app.route("/", methods = ["GET","PUT"])
def index(rt):
print('route: ' + rt)
the above prints this in my terminal:
$ python test.py
['GET', 'PUT']
route: /
Any insight would be appreciated.
Answer: `@app.route("/", methods = ["GET","PUT"])` is an executable statement: it
calls the `route()` method of the app object. Since it's at module level, it
will be executed when the script is imported.
Now, the _result_ of calling `app.route(...)` is a function, and because
you've used the `@` to mark it as a decorator, that function will wrap
`index`. Note that the syntax is just a shortcut for this:
index = app.route(...)(index)
in other words, Python will call the function returned by `app.route()` with
`index` as a parameter, and store the result as the new `index` function.
However, you're missing a level here. A normal decorator, without params, is
written like this:
@foo
def bar()
pass
and when the module is imported, `foo()` is run and returns a function that
wraps `bar`. But you're calling your `route()` function _within_ the decorator
call! So actually your function needs to _return a decorator function_ that
itself returns a function that wraps the original function... headscratching,
to be sure.
Your `route` method should look more like this:
def route(self, *rargs, **kargs):
args = list(rargs)
if kargs:
print(kargs['methods'])
def decorator(f):
def wrapped(index_args):
f(args[0])
return wrapped
return decorator
|
Import statement: Config file Python
Question: I'm maintaining a dictionary and that is loaded inside the config file. The
dictionary is loaded from a JSON file.
**In config.py**
name_dict = json.load(open(dict_file))
I'm importing this config file in several other scripts(file1.py,
file2.py,...,filen.py) using
import config
statement. My question is when will the config.py script be executed ? I'm
sure it wont be executed for every import call that is made inside my multiple
scripts. But, what exactly happens when an import statement is called.
Answer: The top-level code in a module is executed once, the first time you `import`
it. After that, the module object will be found in `sys.modules`, and the code
will not be re-executed to re-generate it.
There are a few exceptions to this:
* `reload`, obviously.
* Accidentally importing the same module under two different names (e.g., if the module is in a package, and you've got some directory in the middle of the package in `sys.path`, you could end up with `mypackage.mymodule` and `mymodule` being two copies of the same thing, in which case the code gets run twice).
* Installing import hooks/custom imported that replace the standard behavior.
* Explicitly monkeying with `sys.modules`.
* Directly calling functions out of `imp`/`importlib` or the like.
* Certain cases with `multiprocessing` (and modules that use it indirectly, like `concurrent.futures`).
* * *
For Python 3.1 and later, this is all described in detail under [The import
system](http://docs.python.org/3/reference/import.html). In particular, look
at the Searching section. (The `multiprocessing`-specific cases are described
for that module.)
For earlier versions of Python, you pretty much have to infer the behavior
from a variety of different sources and either reading the code or
experimenting. However, the well-documented new behavior is intended to work
like the old behavior except in specifically described ways, so you can
usually get away with reading the 3.x docs even for 2.x.
* * *
Note that _in general_ , you don't want to rely on whether top-level code in
the module is run once or multiple times. For example, given a top-level
function definition, as long as you never compare function objects, or rebind
any globals that it (meaning the definition itself, not just the body) depends
on, it doesn't make any difference. However, there are some exceptions to
that, and loading start-time config files is a perfect example of an
exception.
|
Python Fabric Git Pull Merge Message
Question: I've got **Python Fabric** running nicely, however **I have one problem**.
When doing `$ fab deploy` I always get a **Merge popup**
Please enter a commit message to explain why this merge is necessary,
especially if it merges an updated upstream into a topic branch.
I don't understand why it always does this. If I do the exact same command in
SSH to pull my git repo it works without a merge issue.
I will say I'm on Windows 8 and pulling to linux if that matters. The Line
endings shouldnt be an issue, it never has.
This is the **fabfile.py**
from fabric.api import *
from fabric.colors import *
env.user = 'username'
env.host_string = '99.99.0.99'
def deploy(branch = 'master'):
path = '/var/www/mysite/htdocs'
with cd(path):
run("git pull origin {0}".format(branch))
def commit(branch = 'master'):
local('git add -u')
local('git add .')
message = prompt("commit msg: ")
local('git commit -m "{0}"'.format(message))
local('git push origin {0}'.format(branch))
Answer: It is asking you to do merges because the pulls are not fast-forward merges.
Check that your branches are not farckled and you don't have rouge commits on
the deployment side.
|
Not able to import getpass in python
Question: I have a requirement to input username and password from the console. For the
password I am using
password = getpass.getpass('Enter password')
I have used `import getpass` But getting
ImportError : no module named getpass
Also tried setting the pythonpath using
export pythonpath=/usr/lib/python2.4/site-packages:/usr/lib/python2.4
Code:
#!/usr/bin/python2.4
import sys
import getpass
WL_USER = raw_input('Enter the username to login to BI EM:')
WL_PASSWD = getpass.getpass('Enter the password:')
HOST_NAME = raw_input('Enter the BI host URL')
WL_PORT = raw_input('Enter the admin port for BI')
error:
ImportError: no module named getpass
One important thing is that I am trying to run the script as a wlst script
i.e. trying to edit the attribute of an Mbean. So the execution goes like
this: /home/wlserver_10.3/common/bin/wlst.sh test.py
I tried to execute the script as python test.py It executes fine. So it looks
like there is some issue with wlst. Need assistance on this.
Answer: The argument `getpass.getpass()` was added in python 2.5. Check the old
manual, <http://docs.python.org/release/2.4/lib/module-getpass.html>
|
TypeError: 'Undefined' object is not iterable?
Question: The following is the mako template I have created
<%inherit file="/openerp/controllers/templates/base_dispatch.mako"/>
<%def name="header()">
<title>${_("Otp")}</title>
<script type="text/javascript">alert("OTP PAGE");</script>
</%def>
<%def name="content()">
<table width="100%">
<tr><%include file="header.mako"/></tr>
</table>
</br>
<table class="view" cellpadding="0" cellspacing="0" style="padding-top: 10px; border:none;" align="center">
<tr>
<td style="padding:35px 10px 5px 35px; width="450" align="center">
<form action="${py.url(target)}" method="post" name="otpform" id="otpform" style="padding-bottom: 5px; min-width: 100px;">
% for key, value in origArgs.items():
<input type="hidden" name="${key}" value="${value}"/>
% endfor
<input name="otp_action" value="otp" type="hidden"/>
<fieldset class="box" style="width:300px">
<legend style="padding: 4px;">
<img src="/openerp/static/images/stock/stock_person.png" alt=""/>
</legend>
<div class="box2" style="padding: 5px 5px 20px 5px">
<b>Please enter SMS code</b>
<table width="" cellspacing="2px" cellpadding="0" style="border:none;">
<tr>
<td class="label"><label for="otp">${_("Otp:")}</label></td>
<td style="padding: 3px;"><input type="text" id="otp" name="otp" class="db_user_pass" value="${otp}" autofocus="true"/></td>
</tr>
<tr>
<td></td>
<td class="db_login_buttons">
<button type="submit" class="static_boxes">${_("Otp")}</button>
</td>
</tr>
</table>
</div>
</fieldset>
</form>
</td>
</tr>
</table>
<%include file="footer.mako"/>
</%def>
And the python file for the template is
import re
from openobject.controllers import BaseController
import cherrypy
from openerp.utils import rpc
from mako.lookup import TemplateLookup
from mako.template import Template
from openobject import tools
import openobject
from openobject.tools import expose, url, redirect, validate, error_handler
import formencode
import base64
import time
class OTP(BaseController):
_cp_path = "/openerp/otp"
msg = {
}
def __init__(self, *args, **kwargs):
super(OTP, self).__init__(*args, **kwargs)
self._msg = {}
@expose()
def index(self, *args, **kw):
print '>>>>>>>>>>>>>>>>>>>>>>>INDEX<<<<<<<<<<<<<<<<<<<<<<<<<<'
self.msg = {}
target='/'
url='socket://localhost:8070'
action='otp'
info=''
info = None
message=''
origArgs=self.get_orig_args(kw)
self.otp_check(target, action, message, origArgs)
@expose(template="/openerp/controllers/templates/otp.mako")
def otp_check(self, target, action=None, message=None, origArgs={}):
print '>>>>>>>>>>>>>>>>>>>>>>>otp_check<<<<<<<<<<<<<<<<<<<<<<<<<<'
target='/'
url='socket://localhost:8070'
action='otp'
info=''
info = None
return dict(target=target, url=url, action=action, message=message, origArgs=origArgs, info=info)
def get_orig_args(self,kw):
if not kw.get('otp_action'):
return kw
new_kw = kw.copy()
clear_login_fields(new_kw)
return new_kw
# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
But on running it I am getting the following error in browser.
500 Internal Server Error
The server encountered an unexpected condition which prevented it from fulfilling the request.
Traceback (most recent call last):
File "/usr/lib/pymodules/python2.6/cherrypy/_cprequest.py", line 606, in respond
cherrypy.response.body = self.handler()
File "/usr/lib/pymodules/python2.6/cherrypy/_cpdispatch.py", line 25, in __call__
return self.callable(*self.args, **self.kwargs)
File "/home/zbeanz/workspace/Sms_authentication/openerp-web-6.0.4/openobject/tools/_expose.py", line 182, in func_wrapper
res = func(*args, **kw)
File "/home/zbeanz/workspace/Sms_authentication/openerp-web-6.0.4/openobject/controllers/_root.py", line 90, in default
return request.handler()
File "/usr/lib/pymodules/python2.6/cherrypy/_cpdispatch.py", line 25, in __call__
return self.callable(*self.args, **self.kwargs)
File "/home/zbeanz/workspace/Sms_authentication/openerp-web-6.0.4/openobject/tools/_expose.py", line 182, in func_wrapper
res = func(*args, **kw)
File "/home/zbeanz/workspace/Sms_authentication/openerp-web-6.0.4/addons/openerp/controllers/otp.py", line 83, in index
self.otp_check(target, action, message, origArgs)
File "/home/zbeanz/workspace/Sms_authentication/openerp-web-6.0.4/openobject/tools/_expose.py", line 222, in func_wrapper
return render_template(_template, res).encode("utf-8")
File "/home/zbeanz/workspace/Sms_authentication/openerp-web-6.0.4/openobject/tools/_expose.py", line 141, in render_template
return utils.NoEscape(template.render_unicode(**kw))
File "/usr/lib/pymodules/python2.6/mako/template.py", line 138, in render_unicode
return runtime._render(self, self.callable_, args, data, as_unicode=True)
File "/usr/lib/pymodules/python2.6/mako/runtime.py", line 364, in _render
_render_context(template, callable_, context, *args, **_kwargs_for_callable(callable_, data))
File "/usr/lib/pymodules/python2.6/mako/runtime.py", line 381, in _render_context
_exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
File "/usr/lib/pymodules/python2.6/mako/runtime.py", line 414, in _exec_template
callable_(context, *args, **kwargs)
File "_openobject_controllers_templates_base_mako", line 61, in render_body
File "/usr/lib/pymodules/python2.6/mako/runtime.py", line 255, in <lambda>
return lambda *args, **kwargs:callable_(self.context, *args, **kwargs)
File "_openerp_controllers_templates_otp_mako", line 89, in render_content
TypeError: 'Undefined' object is not iterable
What is causing this error ?
Answer: The error description is very clear.
'Undefined' object is not iterable
i.e you have a list object and try to iterate in your mako file. But in
runtime the object is not assigned with value. so the object is undefined. In
your case you iterate only one variable
% for key, value in origArgs.items():
<input type="hidden" name="${key}" value="${value}"/>
% endfor
check if variable **origArgs** has got values while running. It's good to
handle this kind of exceptions like below
%if origArgs:
% for key, value in origArgs.items():
<input type="hidden" name="${key}" value="${value}"/>
% endfor
%endif
If that's not the one causing error, then check for the iterables in file
"/openerp/controllers/templates/base_dispatch.mako". You must be able to get
it. If still no luck, leave a comment below. Cheers!!
|
Trying to run KIVY, for the first time
Question: I'm trying to run kivy for the first time. Im using a default program.
from kivy.app import App
from kivy.uix.widget import Widget
class PongGame(Widget):
pass
class PongApp(App):
def build(self):
return PongGame()
if __name__ == '__main__':
PongApp().run()
I get this error:
##################################
done bootstraping kivy...have fun!\n
running "python.exe C:\Python27\hello.py" \n
Traceback (most recent call last):
File "C:\Python27\hello.py", line 1, in <module>
from kivy.app import App
ImportError: No module named kivy.app
Press any key to continue . . .
A lot of people have raised the issue online, but no one has mentioned the
right solution.
Answer: **UPDATE** : based on the error you're getting—which you just pasted now,
after my original response below—, you seem to be missing not only PyGame but
Kivy itself. Go ahead and run `pip install kivy`.
But before you do that, I'd recommend you take a look at
[virtualenv](http://www.virtualenv.org/en/latest/) and install all your Python
packages specific to this project in a virtualenv created for that project. If
you don't want that, you have to run `sudo pip install kivy` to install Kivy
globally (assuming you're on OS X or Linux). On Windows, `sudo` should not be
needed.
(Also, I'm sure the information below will be useful as well—since you don't
even have Kivy, it must mean that you would have run into problems for not
having PyGame either once would have installed Kivy.)
**ORIGINAL ANSWER:**
**Short version:**
You're missing PyGame, which is a dependency of Kivy.
**Long version:**
Since you didn't tell us what the error was, I went ahead and ran your code on
my OS X 10.8 machine and got this:
$ python main.py
[INFO ] Kivy v1.7.2
...
[CRITICAL] [Window ] Unable to find any valuable Window provider at all!
[CRITICAL] [App ] Unable to get a Window, abort.
googling that error landed me on
<http://kivy.org/docs/installation/troubleshooting-macosx.html>.
So I went ahead and installed PyGame with the help of
<http://juliaelman.com/blog/2013/04/02/installing-pygame-on-osx-mountain-
lion/>; except I installed it in a virtualenv:
$ pip install hg+http://bitbucket.org/pygame/pygame
after that:
$ python yourcode.py
[INFO ] Kivy v1.7.2
Purge log fired. Analysing...
Purge finished !
[INFO ] [Logger ] Record log in /Users/erik.allik/.kivy/logs/kivy_13-10-01_2.txt
[INFO ] [Factory ] 144 symbols loaded
[DEBUG ] [Cache ] register <kv.lang> with limit=None, timeout=Nones
[DEBUG ] [Cache ] register <kv.image> with limit=None, timeout=60s
...
[INFO ] [OSC ] using <multiprocessing> for socket
[DEBUG ] [Base ] Create provider from mouse
[INFO ] [Base ] Start application main loop
And I get a nice Kivy window popping up!
|
Create name value pairs in python
Question: I have a python script that has the following output stored in a variable
called jvmData:
Stats name=jvmRuntimeModule, type=jvmRuntimeModule#
{
name=HeapSize, ID=1, description=The total memory (in KBytes) in the Java virtual machine run time., unit=KILOBYTE, type=BoundedRangeStatistic, lowWaterMark=1048576, highWaterMark=1048576, current=1048576, integral=0.0, lowerBound=1048576, upperBound=2097152
name=FreeMemory, ID=2, description=The free memory (in KBytes) in the Java virtual machine run time., unit=KILOBYTE, type=CountStatistic, count=348466
name=UsedMemory, ID=3, description=The amount of used memory (in KBytes) in the Java virtual machine run time., unit=KILOBYTE, type=CountStatistic, count=700109
name=UpTime, ID=4, description=The amount of time (in seconds) that the Java virtual machine has been running., unit=SECOND, type=CountStatistic, count=3706565
name=ProcessCpuUsage, ID=5, description=The CPU Usage (in percent) of the Java virtual machine., unit=N/A, type=CountStatistic, count=0
}
What I would like to do is simply print out name/value pairs for the important
parts, which in this case would simply be:
HeapSize=1048576
FreeMemory=348466
UsedMemory=700109
UpTime=3706565
ProcessCpuUsage=0
Im not at all good with python :) The only solution in my head seems very
long-winded? Split the lines, throw away first, second and last lines, then
loop through each line with different cases (sometimes current, sometimes
count) for finding the length of string, etc etc
Perhaps (well definitely) I am missing something some nice function I can use
to put these into the equivalent of a java hashmap or something?
Answer: The "equivalent of a java HashMap" would be called a dictionary in python. As
for how to parse this, just iterate over the lines that contain the data, make
a dict of all key/value pairs in the line and have a special case for the
`HeapSize`:
jvmData = "..." #the string holding the data
jvmLines = jvmData.split("\n") #a list of the lines in the string
lines = [l.strip() for l in jvmLines if "name=" in l] #filter all data lines
result = {}
for line in lines:
data = dict(s.split("=") for s in line.split(", "))
#the value is in "current" for HeapSize or in "count" otherwise
value = data["current"] if data["name"] == "HeapSize" else data["count"]
result[data["name"]] = value
As you seem to be stuck on Jython2.1, here's a version that should work with
it (obviously untested). Basically the same as above, but with the list
comprehension and generator expression replaced by `filter` and `map`
respectively, and without using the ternary `if/else` operator:
jvmData = "..." #the string holding the data
jvmLines = jvmData.split("\n") #a list of the lines in the string
lines = filter(lambda x: "name=" in x, jvmLines) #filter all data lines
result = {}
for line in lines:
data = dict(map(lambda x: x.split("="), line.split(", ")))
if data["name"] == "HeapSize":
result[data["name"]] = data["current"]
else:
result[data["name"]] = data["count"]
|
Python dealing with months and years in arrays
Question: newbie question,
I have three arrays, one with years, one with months and one with my data.
The years array has which year the data occurs in, but as the data is
collected monthly, I have a lot of repeat years, eg
`[1996,1997,...,1997,1998,...,1998,1999 etc]`
Then in the array I have `[01,02,...,11,12,01,02, etc]`
Is there anyway to amalgamate these two arrays into one, and then plot them vs
my data?
I have tried multiplying the second array by `1/12` and adding it to the first
array, but would prefer a more elegant solution. Any tips?
Thank you.
Answer: You could use `zip` to combine the years and months into `datetime.date`
objects:
dates = [DT.date(y,m,1) for y, m in zip(years, months)]
To plot using [matplotlib](http://matplotlib.org/):
import matplotlib.pyplot as plt
import datetime as DT
import numpy as np
years = [1996]+[1997]*12+[1998]*12
months =[12]+range(1,13)+range(1,13)
dates = [DT.date(y,m,1) for y, m in zip(years, months)]
values = np.random.random(len(dates))
plt.plot(dates, values)
plt.show()
|
Python-Twitter script works at home and not at University. Deadline REALLY soon
Question: I've written quite a simple python script that pulls in tweets and turns on a
GPIO if a filter is matched. I've tried it at home and it works really well,
however, on the University network it seems not to be able to connect to
twitter.
The details of the University network are WIRELESS SSID: Uni-WiFi WPA2
Enterprise
It uses PEAP (MSCHAPv2) to connect, meaning that I need to type in my
university username and password. The network is connected at present and I
can browse the internet, but when I launch the python script I get the error:
urllib2.HTTPError: HTTP Error 401: Unauthorized
Here is the full python script - If any body could help it would be amazing,
this needs handing in really soon!
#!/usr/bin/env python
import twitter
import RPi.GPIO as GPIO ## Import GPIO library
import time ## Import 'time' library. Allows us to use 'sleep'
from termcolor import colored
GPIO.setmode(GPIO.BOARD) ## Use board pin numbering
GPIO.cleanup()
#My app keys and secrets
CONSUMER_KEY = 'TXXGPRg'
CONSUMER_SECRET = 'jRVxtEgf1CQWuan0N8L4a3s'
OAUTH_TOKEN = '528854Jaudhna2K36g4y79oiwUq'
OAUTH_SECRET = 'ZoQEv1deAQ'
FILTER_TAG = u'art' # Can also be just text, like u'idol', but expect a lot more results!
# We want a continuous stream of events which match a given tag, so we need to use the streaming API.
twitter_stream = twitter.TwitterStream(auth=twitter.OAuth(OAUTH_TOKEN,OAUTH_SECRET,CONSUMER_KEY,CONSUMER_SECRET))
# Now, we don't want every single tweet from the stream, so we'll filter to include only specific text, or a specific tag.
iterator = twitter_stream.statuses.filter(track = FILTER_TAG)
# Now, iterator is a generator which yields a new tweet whenever it sees one. We need to loop over it forever.
for tweet in iterator:
print colored(tweet.get(u'user', {}).get(u'name'), 'white', 'on_red'), colored(tweet.get(u'text'), 'cyan')
if "hate" in tweet.get(u'text', u'fake_text_that_never_matches'): # Now, you need to light up the light for 5 seconds, then shut it off.
print colored("Switch turned ON!", "red", 'on_yellow')
GPIO.setup(7, GPIO.OUT)
GPIO.output(7,True)## Switch on pin 7
time.sleep(5)## Wait
GPIO.output(7,False)## Switch off pin 7
print "----------------------------------------------------------------------------------------------------------------------------------------------------"
Answer: Part of the OAuth signature is a timestamp, which is generated when you make
the request. If your server's time differs too much from Twitter's server
time, the Twitter server will reject your request with a 401. So, check the
time being returned by the Twitter server and make sure your local machine
that is generating the signature matches the same time.
|
Fast peak-finding and centroiding in python
Question: I am trying to develop a fast algorithm in python for finding peaks in an
image and then finding the centroid of those peaks. I have written the
following code using the scipy.ndimage.label and ndimage.find_objects for
locating the objects. This seems to be the bottleneck in the code, and it
takes about 7 ms to locate 20 objects in a 500x500 image. I would like to
scale this up to larger (2000x2000) image, but then the time increases to
almost 100 ms. So, I'm wondering if there is a faster option.
Here is the code that I have so far, which works, but is slow. First I
simulate my data using some gaussian peaks. This part is slow, but in practice
I will be using real data, so I don't care too much about speeding that part
up. I would like to be able to find the peaks very quickly.
import time
import numpy as np
import matplotlib.pyplot as plt
import scipy.ndimage
import matplotlib.patches
plt.figure(figsize=(10,10))
ax1 = plt.subplot(221)
ax2 = plt.subplot(222)
ax3 = plt.subplot(223)
ax4 = plt.subplot(224)
size = 500 #width and height of image in pixels
peak_height = 100 # define the height of the peaks
num_peaks = 20
noise_level = 50
threshold = 60
np.random.seed(3)
#set up a simple, blank image (Z)
x = np.linspace(0,size,size)
y = np.linspace(0,size,size)
X,Y = np.meshgrid(x,y)
Z = X*0
#now add some peaks
def gaussian(X,Y,xo,yo,amp=100,sigmax=4,sigmay=4):
return amp*np.exp(-(X-xo)**2/(2*sigmax**2) - (Y-yo)**2/(2*sigmay**2))
for xo,yo in size*np.random.rand(num_peaks,2):
widthx = 5 + np.random.randn(1)
widthy = 5 + np.random.randn(1)
Z += gaussian(X,Y,xo,yo,amp=peak_height,sigmax=widthx,sigmay=widthy)
#of course, add some noise:
Z = Z + scipy.ndimage.gaussian_filter(0.5*noise_level*np.random.rand(size,size),sigma=5)
Z = Z + scipy.ndimage.gaussian_filter(0.5*noise_level*np.random.rand(size,size),sigma=1)
t = time.time() #Start timing the peak-finding algorithm
#Set everything below the threshold to zero:
Z_thresh = np.copy(Z)
Z_thresh[Z_thresh<threshold] = 0
print 'Time after thresholding: %.5f seconds'%(time.time()-t)
#now find the objects
labeled_image, number_of_objects = scipy.ndimage.label(Z_thresh)
print 'Time after labeling: %.5f seconds'%(time.time()-t)
peak_slices = scipy.ndimage.find_objects(labeled_image)
print 'Time after finding objects: %.5f seconds'%(time.time()-t)
def centroid(data):
h,w = np.shape(data)
x = np.arange(0,w)
y = np.arange(0,h)
X,Y = np.meshgrid(x,y)
cx = np.sum(X*data)/np.sum(data)
cy = np.sum(Y*data)/np.sum(data)
return cx,cy
centroids = []
for peak_slice in peak_slices:
dy,dx = peak_slice
x,y = dx.start, dy.start
cx,cy = centroid(Z_thresh[peak_slice])
centroids.append((x+cx,y+cy))
print 'Total time: %.5f seconds\n'%(time.time()-t)
###########################################
#Now make the plots:
for ax in (ax1,ax2,ax3,ax4): ax.clear()
ax1.set_title('Original image')
ax1.imshow(Z,origin='lower')
ax2.set_title('Thresholded image')
ax2.imshow(Z_thresh,origin='lower')
ax3.set_title('Labeled image')
ax3.imshow(labeled_image,origin='lower') #display the color-coded regions
for peak_slice in peak_slices: #Draw some rectangles around the objects
dy,dx = peak_slice
xy = (dx.start, dy.start)
width = (dx.stop - dx.start + 1)
height = (dy.stop - dy.start + 1)
rect = matplotlib.patches.Rectangle(xy,width,height,fc='none',ec='red')
ax3.add_patch(rect,)
ax4.set_title('Centroids on original image')
ax4.imshow(Z,origin='lower')
for x,y in centroids:
ax4.plot(x,y,'kx',ms=10)
ax4.set_xlim(0,size)
ax4.set_ylim(0,size)
plt.tight_layout
plt.show()
The results for size=500: 
EDIT: If the number of peaks is large (~100) and the size of the image is
small, then the bottleneck is actually the centroiding part. So, perhaps the
speed of this part also needs to be optimized.
Answer: Your method for finding the peaks (simple thresholding) is of course very
sensitive to the choice of threshold: set it too low and you'll "detect"
things that are not peaks; set it too high and you'll miss valid peaks.
There are more robust alternatives, that will detect all the local maxima in
the image intensity regardless of their intensity value. My preferred one is
applying a dilation with a small (5x5 or 7x7) structuring element, then find
the pixels where the original image and its dilated version have the same
value. This works because, by definition, dilation(x, y, E, img) = { max of
img within E centered at pixel (x,y) }, and therefore dilation(x, y, E, img) =
img(x, y) whenever (x,y) is the location of a local maximum at the scale of E.
With a fast implementation of the morphological operators (e.g. the one in
OpenCV) this algorithm is linear in the size of the image in both space and
time (one extra image-sized buffer for the dilated image, and one pass on
both). In a pinch, it can also be implemented on-line without the extra buffer
and a little extra complexity, and it's still linear time.
To further robustify it in the presence of salt-and-pepper or similar noise,
which may introduce many false maxima, you can apply the method twice, with
structuring elements of different size (say, 5x5 and 7x7), then retain only
the stable maxima, where stability can be defined by unchanging position of
the maxima, or by position not changing by more than one pixel, etc.
Additionally, you may want to suppress low nearby maxima when you have reason
to believe they are due to noise. An efficient way to do this is to first
detect all the local maxima as above, sort them descending by height, then go
down the sorted list and keep them if their value in the image has not changed
and, if they are kept, set to zero all the pixels in a (2d+1) x (2d+1)
neighborhood of them, where d is the min distance between nearby maxima that
you are willing to tolerate.
|
easy_install virtualenvwrapper error in CentOS 5.8 64bit
Question: Installed Python 2.6.1 (with /opt prefix), setuptools 0.6c9, and virtualenv
onto CentOS 5.8 64bit.(I was mostly following the instructions from here:
<http://bda.ath.cx/blog/2009/04/08/installing-python-26-in-centos-5-or-
rhel5/comment-page-1/#comment-15422>)
I got stuck when I tried to install virtualenwrapper and got the following
errors:
/opt/bin/easy_install virtualenvwrapper
Searching for virtualenvwrapper
Reading http://pypi.python.org/simple/virtualenvwrapper/
Best match: virtualenvwrapper 4.1.1
Downloading https://pypi.python.org/packages/source/v/virtualenvwrapper/virtualenvwrapper-4.1.1.tar.gz#md5=f18f2c612b936583a8ec0f7114b6637e
Processing virtualenvwrapper-4.1.1.tar.gz
Running virtualenvwrapper-4.1.1/setup.py -q bdist_egg –dist-dir /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/egg-dist-tmp-oaCjsg
Checking .pth file support in .
/opt/bin/python2.6 -E -c pass
Searching for pbr>=0.5.19
Reading http://pypi.python.org/simple/pbr/
Best match: pbr 0.5.21
Downloading https://pypi.python.org/packages/source/p/pbr/pbr-0.5.21.tar.gz#md5=1dafd1ef666b9bce4d880170ddc39387
Processing pbr-0.5.21.tar.gz
Running pbr-0.5.21/setup.py -q bdist_egg –dist-dir /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/temp/easy_install-Prh_Pq/pbr-0.5.21/egg-dist-tmp-PLfFJs
Installed /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/pbr-0.5.21-py2.6.egg
Searching for pip>=1.0
Reading http://pypi.python.org/simple/pip/
Best match: pip 1.4.1
Downloading https://pypi.python.org/packages/source/p/pip/pip-1.4.1.tar.gz#md5=6afbb46aeb48abac658d4df742bff714
Processing pip-1.4.1.tar.gz
Running pip-1.4.1/setup.py -q bdist_egg –dist-dir /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/temp/easy_install-N07Olv/pip-1.4.1/egg-dist-tmp-cH_0sg
warning: no files found matching ‘*.html’ under directory ‘docs’
warning: no previously-included files matching ‘*.rst’ found under directory ‘docs/_build’
no previously-included directories found matching ‘docs/_build/_sources’
Installed /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/pip-1.4.1-py2.6.egg
/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/dist.py:245: UserWarning: Module pbr was already imported from /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/temp/easy_install-Prh_Pq/pbr-0.5.21/pbr/__init__.py, but /tmp/easy_install-gIYCea/virtualenvwrapper-4.1.1/pbr-0.5.21-py2.6.egg is being added to sys.path
Traceback (most recent call last):
File “/opt/bin/easy_install”, line 8, in
load_entry_point(‘setuptools==0.6c9′, ‘console_scripts’, ‘easy_install’)()
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 1671, in main
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 1659, in with_ei_usage
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 1675, in
File “/opt/lib/python2.6/distutils/core.py”, line 152, in setup
dist.run_commands()
File “/opt/lib/python2.6/distutils/dist.py”, line 975, in run_commands
self.run_command(cmd)
File “/opt/lib/python2.6/distutils/dist.py”, line 995, in run_command
cmd_obj.run()
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 211, in run
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 446, in easy_install
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 476, in install_item
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 655, in install_eggs
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 930, in build_and_install
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/command/easy_install.py”, line 919, in run_setup
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/sandbox.py”, line 27, in run_setup
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/sandbox.py”, line 63, in run
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/sandbox.py”, line 29, in
File “setup.py”, line 7, in
File “/opt/lib/python2.6/distutils/core.py”, line 113, in setup
_setup_distribution = dist = klass(attrs)
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/dist.py”, line 223, in __init__
File “/opt/lib/python2.6/distutils/dist.py”, line 270, in __init__
self.finalize_options()
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/setuptools/dist.py”, line 256, in finalize_options
File “/opt/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg/pkg_resources.py”, line 1913, in load
ImportError: No module named core
No idea what's going on. Can anyone help?
Answer: it turned out by using a newer version of setuptools solved the problem.
|
Django app missing after import?
Question: I'm working on a django project using win7 with aptana3/pydev . I have a
project called mytest and I'm trying to import an app called 'django-mailbox'
into my project (<http://django-
mailbox.readthedocs.org/en/latest/topics/installation.html>)
Following the directions I performed:
~tools/virtualenvs/mytest
$ pip install django-mailbox
Downloading/unpacking django-mailbox
Downloading django-mailbox-3.0.2.tar.gz
Running setup.py egg_info for package django-mailbox
Downloading/unpacking six (from django-mailbox)
Downloading six-1.4.1.tar.gz
Running setup.py egg_info for package six
Installing collected packages: django-mailbox, six
Running setup.py install for django-mailbox
Running setup.py install for six
Successfully installed django-mailbox six
Cleaning up...
I have also added:
INSTALLED_APPS = (
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'django_mailbox',
to my settings.py file.
I was expecting to see the 'django_mailbox' directory within the 'mytest'
dirctory, but its not. What happened, and where is it?
edit:
My directory structure is:
|-development
|---projects
|---tools
|-----PortableGit
|-----Portablepython - ( actually installed in here ) ( Global files ? )
|-----Virtalenvs
|--------mytest ( I thought it should be installed here )
|--------otherfile
/development/tools/virtualenvs/mytest
$ find ./ -type d | sed -e 's/[^-][^\/]*\//--/g;s/--/ |-/'
|-
|-mytest
|-chat1
|-Lib
|---encodings
|---site-packages
|-----setuptools
|-------command
|-------tests
|-------_backport
|---------hashlib
|-----_markerlib
|-----setuptools-0.9.8-py2.7.egg-info
|-----pip
|-------backwardcompat
|-------commands
|-------vcs
|-------vendor
|---------distlib
|-----------_backport
|---------html5lib
|-----------filters
|-----------serializer
|-----------treebuilders
|-----------treewalkers
|-----------trie
|-----pip-1.4.1-py2.7.egg-info
|---distutils
|-Include
|---pygame
|---pycairo
|---pygtk-2.0
|-----pygtk
|-Scripts
Answer: In your `virtualenv`, it is stored very similar to the Python installation of
the packages.
<path_to_virtualenv>/lib/python2.7/site-packages/
|
Jquery ajax with google app engine post method
Question: Just trying to learn using ajax with appengine,started with the post
method,but it does not work. This is my HTML Code for the page
<html>
<head>
<title> Hello </title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js">
</script>
<script>
var data={"name":"Hola"};
$(document).ready(function(){
$('#subbut').click(function(){
$.ajax({
url: '/test',
type: 'POST',
data: data,
success: function(data,status){
alert("Data" + data +"status"+status);
}
});
});
});
</script>
</head>
<body>
<form method="post" action="/test">
<input type="submit" id="subbut">
</form>
<div id="success"> </div>
</body>
</html>
Here goes my python code to render the above html code , its handler is /test1
from main import *
class TestH1(Handler):
def get(self):
self.render('tester.html')
And this is the python script to which AJAX request must be sent to,handler is
/test.
from main import *
import json
class TestH(Handler):
def post(self):
t=self.request.get('name')
output={'name':t+" duck"}
output=json.dumps(output)
self.response.out.write(output)
Expected behavior is that when i click on submit button,i get an alert message
saying "Hola duck" , get nothing instead. Any help would be appreciated as i
am just starting with AJAX and Jquery withGAE
Answer: At first, I suppose you should suppress default behavior of form submitting
when you press submit button by adding "return false" to the .click function.
But I suppose it would be better to use just
<input type="button" id="subbut">
instead (even without form).
Then you should add "dataType: 'json'" to your ajax call to tell jQuery what
type of data you expect from server. Doing this you will be able to get
response data by property names like "data.name". So:
var data={"name":"Hola"};
$(document).ready(function(){
$('#subbut').click(function(){
$.ajax({
url: '/test',
type: 'POST',
data: data,
dataType: 'json',
success: function(data,status){
alert(data.name);
alert("Data" + data +"status"+status);
}
});
return false;
});
});
and it would be better if you set appropriate content type header to your
response:
response.headers = {'Content-Type': 'application/json; charset=utf-8'}
self.response.out.write(output)
|
Django: ImproperlyConfigured: The SECRET_KEY setting must not be empty
Question: I am trying to set up multiple setting files (development, production, ..)
that include some base settings. Cannot succeed though. When I try to run
`./manage.py runserver` I am getting the following error:
(cb)clime@den /srv/www/cb $ ./manage.py runserver
ImproperlyConfigured: The SECRET_KEY setting must not be empty.
Here is my settings module:
(cb)clime@den /srv/www/cb/cb/settings $ ll
total 24
-rw-rw-r--. 1 clime clime 8230 Oct 2 02:56 base.py
-rw-rw-r--. 1 clime clime 489 Oct 2 03:09 development.py
-rw-rw-r--. 1 clime clime 24 Oct 2 02:34 __init__.py
-rw-rw-r--. 1 clime clime 471 Oct 2 02:51 production.py
Base settings (contain SECRET_KEY):
(cb)clime@den /srv/www/cb/cb/settings $ cat base.py:
# Django base settings for cb project.
import django.conf.global_settings as defaults
DEBUG = False
TEMPLATE_DEBUG = False
INTERNAL_IPS = ('127.0.0.1',)
ADMINS = (
('clime', '[email protected]'),
)
MANAGERS = ADMINS
DATABASES = {
'default': {
#'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'.
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'cwu', # Or path to database file if using sqlite3.
'USER': 'clime', # Not used with sqlite3.
'PASSWORD': '', # Not used with sqlite3.
'HOST': '', # Set to empty string for localhost. Not used with sqlite3.
'PORT': '', # Set to empty string for default. Not used with sqlite3.
}
}
# Local time zone for this installation. Choices can be found here:
# http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
# although not all choices may be available on all operating systems.
# In a Windows environment this must be set to your system time zone.
TIME_ZONE = 'Europe/Prague'
# Language code for this installation. All choices can be found here:
# http://www.i18nguy.com/unicode/language-identifiers.html
LANGUAGE_CODE = 'en-us'
SITE_ID = 1
# If you set this to False, Django will make some optimizations so as not
# to load the internationalization machinery.
USE_I18N = False
# If you set this to False, Django will not format dates, numbers and
# calendars according to the current locale.
USE_L10N = False # TODO: make this true and accustom date time input
DATE_INPUT_FORMATS = defaults.DATE_INPUT_FORMATS + ('%d %b %y', '%d %b, %y') # + ('25 Oct 13', '25 Oct, 13')
# If you set this to False, Django will not use timezone-aware datetimes.
USE_TZ = True
# Absolute filesystem path to the directory that will hold user-uploaded files.
# Example: "/home/media/media.lawrence.com/media/"
MEDIA_ROOT = '/srv/www/cb/media'
# URL that handles the media served from MEDIA_ROOT. Make sure to use a
# trailing slash.
# Examples: "http://media.lawrence.com/media/", "http://example.com/media/"
MEDIA_URL = '/media/'
# Absolute path to the directory static files should be collected to.
# Don't put anything in this directory yourself; store your static files
# in apps' "static/" subdirectories and in STATICFILES_DIRS.
# Example: "/home/media/media.lawrence.com/static/"
STATIC_ROOT = '/srv/www/cb/static'
# URL prefix for static files.
# Example: "http://media.lawrence.com/static/"
STATIC_URL = '/static/'
# Additional locations of static files
STATICFILES_DIRS = (
# Put strings here, like "/home/html/static" or "C:/www/django/static".
# Always use forward slashes, even on Windows.
# Don't forget to use absolute paths, not relative paths.
)
# List of finder classes that know how to find static files in
# various locations.
STATICFILES_FINDERS = (
'django.contrib.staticfiles.finders.FileSystemFinder',
'django.contrib.staticfiles.finders.AppDirectoriesFinder',
# 'django.contrib.staticfiles.finders.DefaultStorageFinder',
)
# Make this unique, and don't share it with anybody.
SECRET_KEY = '8lu*6g0lg)9z!ba+a$ehk)xt)x%rxgb$i1&022shmi1jcgihb*'
# List of callables that know how to import templates from various sources.
TEMPLATE_LOADERS = (
'django.template.loaders.filesystem.Loader',
'django.template.loaders.app_directories.Loader',
# 'django.template.loaders.eggs.Loader',
)
TEMPLATE_CONTEXT_PROCESSORS = (
'django.contrib.auth.context_processors.auth',
'django.core.context_processors.request',
'django.core.context_processors.debug',
'django.core.context_processors.i18n',
'django.core.context_processors.media',
'django.core.context_processors.static',
'django.core.context_processors.tz',
'django.contrib.messages.context_processors.messages',
'web.context.inbox',
'web.context.base',
'web.context.main_search',
'web.context.enums',
)
MIDDLEWARE_CLASSES = (
'django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'watson.middleware.SearchContextMiddleware',
'debug_toolbar.middleware.DebugToolbarMiddleware',
'middleware.UserMemberMiddleware',
'middleware.ProfilerMiddleware',
'middleware.VaryOnAcceptMiddleware',
# Uncomment the next line for simple clickjacking protection:
# 'django.middleware.clickjacking.XFrameOptionsMiddleware',
)
ROOT_URLCONF = 'cb.urls'
# Python dotted path to the WSGI application used by Django's runserver.
WSGI_APPLICATION = 'cb.wsgi.application'
TEMPLATE_DIRS = (
# Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
# Always use forward slashes, even on Windows.
# Don't forget to use absolute paths, not relative paths.
'/srv/www/cb/web/templates',
'/srv/www/cb/templates',
)
INSTALLED_APPS = (
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'south',
'grappelli', # must be before admin
'django.contrib.admin',
'django.contrib.admindocs',
'endless_pagination',
'debug_toolbar',
'djangoratings',
'watson',
'web',
)
AUTH_USER_MODEL = 'web.User'
# A sample logging configuration. The only tangible logging
# performed by this configuration is to send an email to
# the site admins on every HTTP 500 error when DEBUG=False.
# See http://docs.djangoproject.com/en/dev/topics/logging for
# more details on how to customize your logging configuration.
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'filters': {
'require_debug_false': {
'()': 'django.utils.log.RequireDebugFalse'
}
},
'formatters': {
'standard': {
'format' : "[%(asctime)s] %(levelname)s [%(name)s:%(lineno)s] %(message)s",
'datefmt' : "%d/%b/%Y %H:%M:%S"
},
},
'handlers': {
'mail_admins': {
'level': 'ERROR',
'filters': ['require_debug_false'],
'class': 'django.utils.log.AdminEmailHandler'
},
'null': {
'level':'DEBUG',
'class':'django.utils.log.NullHandler',
},
'logfile': {
'level':'DEBUG',
'class':'logging.handlers.RotatingFileHandler',
'filename': "/srv/www/cb/logs/application.log",
'maxBytes': 50000,
'backupCount': 2,
'formatter': 'standard',
},
'console':{
'level':'INFO',
'class':'logging.StreamHandler',
'formatter': 'standard'
},
},
'loggers': {
'django.request': {
'handlers': ['mail_admins'],
'level': 'ERROR',
'propagate': True,
},
'django': {
'handlers':['console'],
'propagate': True,
'level':'WARN',
},
'django.db.backends': {
'handlers': ['console'],
'level': 'DEBUG',
'propagate': False,
},
'web': {
'handlers': ['console', 'logfile'],
'level': 'DEBUG',
},
},
}
LOGIN_URL = 'login'
LOGOUT_URL = 'logout'
#ENDLESS_PAGINATION_LOADING = """
# <img src="/static/web/img/preloader.gif" alt="loading" style="margin:auto"/>
#"""
ENDLESS_PAGINATION_LOADING = """
<div class="spinner small" style="margin:auto">
<div class="block_1 spinner_block small"></div>
<div class="block_2 spinner_block small"></div>
<div class="block_3 spinner_block small"></div>
</div>
"""
DEBUG_TOOLBAR_CONFIG = {
'INTERCEPT_REDIRECTS': False,
}
import django.template.loader
django.template.loader.add_to_builtins('web.templatetags.cb_tags')
django.template.loader.add_to_builtins('web.templatetags.tag_library')
WATSON_POSTGRESQL_SEARCH_CONFIG = 'public.english_nostop'
One of the setting files:
(cb)clime@den /srv/www/cb/cb/settings $ cat development.py
from base import *
DEBUG = True
TEMPLATE_DEBUG = True
ALLOWED_HOSTS = ['127.0.0.1', '31.31.78.149']
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'cwu',
'USER': 'clime',
'PASSWORD': '',
'HOST': '',
'PORT': '',
}
}
MEDIA_ROOT = '/srv/www/cb/media/'
STATIC_ROOT = '/srv/www/cb/static/'
TEMPLATE_DIRS = (
'/srv/www/cb/web/templates',
'/srv/www/cb/templates',
)
Code in `manage.py`:
(cb)clime@den /srv/www/cb $ cat manage.py
#!/usr/bin/env python
import os
import sys
if __name__ == "__main__":
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "cb.settings.development")
from django.core.management import execute_from_command_line
execute_from_command_line(sys.argv)
If I add `from base import *` into `/srv/www/cb/cb/settings/__init__.py`
(which is otherwise empty), it magically starts to work but I don't understand
why. Anyone could explain to me what's going on here? It must be some python
module magic.
**EDIT:** Everything also starts to work if I remove this line from base.py
django.template.loader.add_to_builtins('web.templatetags.cb_tags')
If I remove this line from web.templatetags.cb_tags, it also starts to work:
from endless_pagination.templatetags import endless
I guess it is because, in the end, it leads to
from django.conf import settings
PER_PAGE = getattr(settings, 'ENDLESS_PAGINATION_PER_PAGE', 10)
So it creates some weird circular stuff and game over.
Answer: I had the same error and it turned out to be a circular dependency between
something loaded by the settings and the settings module itself. In my case it
was a middleware class which was named in the settings which itself tried to
load the settings.
|
TypeError: '_csv.reader' object has no attribute '__getitem__' // getting columns?
Question: I'm trying to open a .csv file and put each column in different list:
import csv
CSV = csv.reader(open("AAPL.csv","rb"))
column1 = CSV[0]
column2 = CSV[1]
column3 = CSV[2]
column4 = CSV[2]
column5 = CSV[4]
column6 = CSV[5]
Here is my `AAPL.csv`:
Date Open High Low Close Volume Adj Close
2013-09-27 874.82 877.52 871.31 876.39 1258800 876.39
2013-09-26 878.3 882.75 875 878.17 1259900 878.17
2013-09-25 886.55 886.55 875.6 877.23 1649000 877.23
2013-09-24 886.5 890.1 881.4 886.84 1467000 886.84
2013-09-23 896.15 901.59 885.2 886.5 1777400 886.5
2013-09-20 898.39 904.13 895.62 903.11 4345300 903.11
2013-09-19 905.99 905.99 895.4 898.39 1597900 898.39
2013-09-18 886.35 903.97 883.07 903.32 1934700 903.32
2013-09-17 887.41 888.39 881 886.11 1259400 886.11
2013-09-16 896.2 897 884.87 887.76 1336500 887.76
.............................................................
end of file:
.............................................................
2012-06-29 574.96 58013 572.20 580.07 2519500 580.07
2012-06-28 565.90 566.23 557.21 564.31 1920900 564.31
2012-06-27 567.70 573.99 566.02 569.30 1692300 569.30
2012-06-26 562.76 566.60 559.48 564.68 1350200 564.68
2012-06-25 567.33 568.09 557.35 560.70 1581600 560.70
When I run my code, it returns me the following error:
Traceback (most recent call last):
File "/home/misha/Documents/finance/prices/some_csv.py", line 3, in <module>
column1 = CSV[0]
TypeError: '_csv.reader' object has no attribute '__getitem__'
Is there any pythonic way to open a .csv file and put each column in different
list not using attribute `getitem`?
Thanks.
NOTE: and also i need to skip first row.
Answer: A `csv.reader` instance is an iterable over the lines of the CSV file. If you
want each column in a separate list, you can use the `zip` function:
import csv
with open("AAPL.csv", "rb") as f:
CSV = csv.reader(f)
header = next(CSV) # read the header row
column_data = zip(*CSV) # read data and arrange by columns instead of by rows
# do stuff with column_lists
Note that this reads the whole file in at once. If you have a very large
amount of data in your file, you might want to redesign your algorithms to
work on the data one row at a time as you iterate over the `CSV` object, so
you don't need to hold it all in memory.
|
Python - Formatting specific data within text files
Question: I have a number of log files I need extract and format data. some of these log
files are very big with over 10,000 lines.
can anyone suggest a code sample to help me read a text file, remove unwanted
lines, then edit the remaining lines into a particular format. i haven't been
able to find any previous threads that have what I'm after.
An example of the data I need to edit is below:
136: add student 50000000 35011 / Y01T :Unknown id in field 3 - ignoring line
137: add student 50000000 5031 / Y01S :Unknown id in field 3 - ignoring line
138: add student 50000000 881 / Y01S :Unknown course idnumber in field 4 - ignoring line
139: add student 50000000 5732 / Y01S :Unknown id in field 3 - ignoring line
134: add student 50000000 W250 / Y02S :OK
135: add student 50000000 35033 / Y01T :OK
I need to search the file and delete any line that is suffixed with :OK. Then,
i need to edit the remaining lines in to a CSV format such as:
add,student,50000000,1234 / abcd
Any tips, code snippets, etc would be very helpful and i'll be most grateful.
i'd try it first before asking, but I have little time to self teach python
file access/string formatting. So please allow me to apologise in advance for
not attempting it prior to asking
Answer: This could be a solution:
import sys
if len(sys.argv) != 2:
print 'Add an input file as parameter'
sys.exit(1)
print 'opening file: %s' % sys.argv[1]
with open(sys.argv[1]) as input, open('output', 'w+') as output:
for line in input:
if line is not None:
if line == '\n':
pass
elif 'OK' in line:
pass
else:
new_line = line.split(' ', 7)
output.write('%s,%s,%s,%s / %s\n' % (new_line[1], new_line[2], new_line[3], new_line[4], new_line[6]))
# just for checking purposes let's print the lines
print '%s,%s,%s,%s / %s' % (new_line[1], new_line[2], new_line[3], new_line[4], new_line[6])
Watch out for the output file name!
|
numpy unique strange behaviour
Question: according to the official numpy.unique documentation
(<http://docs.scipy.org/doc/numpy/reference/generated/numpy.unique.html>)
return_index=True should allow me to recover the first occurrences of elements
in an array. However, this does not work for this simple example:
import numpy as np
a = np.array([10,20,30,40,50,60,70,80,3,2,4,3,2,5,2,1,999,1000])
a = np.append(a,np.repeat(999,10000))
u, indices = np.unique(a, return_index=True)
print indices[13], u[13] #according to unique documentation indices[13] should be 16 (i.e. first occurrence of 999 = u[13]), but it is not
This results in:
[mvogelsberger@itc021 ~]$ python test.py
6685 999
Clearly, 6685 is not the index of first occurrence of 999 in the array a. Can
someone clarify? I probably misunderstand the documentation...
Thanks! Mark
Answer: As you've guessed in the comments, this behaviour is indeed [a bug that was
fixed in Numpy
v1.7](https://github.com/numpy/numpy/commit/dbf235169ed3386b359caaa9217f5280bf1d6749)
|
Importing a class into another class in Python
Question: as I'm still learning python I came up to a problem.
Why does this work:
class SomeOtherClass(object):
def __init__(self):
self.number = 10
print(self.number)
def increase(self):
self.number += 1
print(self.number)
class MyMainClass(object):
def __init__(self):
self.otherClass = MyClass()
app = MyMainClass() #Output: 10
app.otherclass.increase() #Output: 11
but this doesn't:
from tkinter import *
class MyMainClass(object):
def __init__(self):
self.tk = Tkinter() # <-- Error: see below.
app = MyMainClass()
app.tk.title("My window")
...
Both times I include a class, but in the second example it says:
> NameError: global name 'Tkinter' is not defined
Where's the difference between those examples and how can I solve this, so I'm
able to use tkinter in my class?
Thanks for your help.
Answer: Perhaps you meant `Tk()`? the `tkinter` module on Python 3.x does not seem to
contain a class `Tkinter`.
As to the meaning of your question and example... well, the examples are
absolutely irrelevant, and the question should simply be "why can't I create
an instance of `Tkinter`" or something.
**Python Lesson:** This is also a good example of why it's a bad idea to use
star imports (i.e `from <module> import *`, because `*` looks like a star).
This imports everything from `tkinter`, but doesn't let you know if something
you thought was there actually isn't
from tkinter import *
whereas this
from tkinter import Tkinter
would have immediately pointed out that (the class) `Tkinter` does not exist
in `tkinter`. Another option that some seem to prefer (incl. myself in some
cases), is `import tkinter` followed by `tkinter.Tk()`, which has the
advantage that it's obvious where a class comes from. Futhermore,
[PEP8](http://www.python.org/dev/peps/pep-0008/#imports) also discourages the
use of star imports (referring to them as "wildcard imports").
|
python itertools: Using cycle with islice
Question: Question:
I have the code below. I want to know why does it not matter whether or not I
include the line with the comment in the code below.
#!/usr/bin/env python
from itertools import *
import time
cc = cycle([ iter([1,2,3]), iter([4]) , iter([5,6]) ] )
p = 3
while p:
try:
for k in cc:
print k.next()
except StopIteration:
p = p - 1
cc = cycle(islice(cc, p)) # this does not matter
Output:
1
4
5
2
6
3
Also checkout `roundrobin` recipe at
<http://docs.python.org/2.7/library/itertools.html>
This code shows that `islice` is impacting `cc`
#!/usr/bin/env python
from itertools import *
import time
cc = cycle([ iter([1,2,3]), iter([4]) , iter([5,6]) ] )
p = 3
while p:
try:
for k in cc:
print k,k.next()
except StopIteration:
print "stop iter"
p = p - 1
cc = cycle(islice(cc, p))
Output
<listiterator object at 0x7f32bc50cfd0> 1
<listiterator object at 0x7f32bc518050> 4
<listiterator object at 0x7f32bc518090> 5
<listiterator object at 0x7f32bc50cfd0> 2
<listiterator object at 0x7f32bc518050> stop iter
<listiterator object at 0x7f32bc518090> 6
<listiterator object at 0x7f32bc50cfd0> 3
<listiterator object at 0x7f32bc518090> stop iter
<listiterator object at 0x7f32bc50cfd0> stop iter
Answer: Short course: the behaviors with and without rebinding `cc` aren't
**generally** the same, but the outputs **happen** to be the same for the
specific input you used.
Long course: let's call your three iterators A, B and C.
Without the `cc` rebinding: A produces 1, B produces 4, C produces 5, A
produces 2, B raises `StopIteration`. `p` drops to 2. Then C produces 6, A
produces 3, and B raises `StopIteration` **again**. `p` drops to 1. C raises
`StopIteration`. `p` drops to 0, and the loop exits.
With the `cc` rebinding: A produces 1, B produces 4, C produces 5, A produces
2, B raises `StopIteration`. `p` drops to 2. All the same so far. The purpose
of the rebinding in the round-robin algorithm is to **remove** exhausted
iterators. It so happens that in this specific example it makes no difference
to the outcome. With the rebinding `islice(cc, 2)` takes "the next two things"
from `cc`, which are, in order, C and A. B is no longer there. Then C and A
are put in a new `cycle`.
Then C produces 6, A produces 3, and C raises `StopIteration`. `p` drops to 1.
The `cc` rebinding gets rid of C (the exhausted iterator), leaving just A in a
new `cycle`. The loop goes around, and A raises `StopIteration`. `p` drops to
0, and we're done.
Of course removing exhausted iterators is crucial to making round-robin work
correctly in general. But, as you've shown, there are specific cases in which
that doesn't matter :-)
## Simple example
A simple case where rebinding `cc` makes a huge difference:
cc = cycle([iter([1,2,3,4,5]), iter([])])
p = 2
With rebinding, we get all 5 values. Without rebinding, we only get 1 and 2.
|
Python object encapsulation security
Question: I have a question, and my decision in choosing Python as a possible language
for a bigger project depends on the answer - which I cannot come up with
myself:
We all know that Python has no _real_ object encapsulation, so there is
nothing like "private" properties of an object. Regarding this issue, Guido
van Rossum says that one can access hidden parts of a foreign object without
being "allowed" to, with "we are all adults", "just don't do it". I can live
perfectly well with that, as long as the software I write is in my own hand,
so I am responsible for my own errors and just can try to avoid such things.
BUT - and here comes my question: What if I provide a plugin framework with
some plugins that have some extension points, and many of the plugins are by
OTHER people, maybe ones that I cannot trust completely.
How do I prevent exposing internals of my framework from being accessed by a
plugin?
Is there a way to achieve this, or is the only way to use Python having
confidence that no one will abuse my API?
Answer: You should never really rely on `private`, `public` etc for security (as in
"protection against malicious code and external threats"). They are meant as
something to keep the programmer from shooting himself in the foot, not as a
(computer) security measure. You can also easily access private member fields
of C++ objects, as long as you bypass static compiler checks and go straight
to the memory, but would you say that C++ lacks true encapsulation?
* For **C++** , see <http://phoxis.org/2012/01/25/accessing-private-data-members-directly-outside-from-its-class-in-c/>
* Same about the **JVM** (and thus **Java**): [How do I read a private field in Java?](http://stackoverflow.com/questions/1196192/how-do-i-read-a-private-field-in-java)
* And (more or less) the same about **CLR** (i.e. **.NET**): [Does reflection breaks the idea of private methods, because private methods can be access outside of the class?](http://stackoverflow.com/questions/3300680/does-reflection-breaks-the-idea-of-private-methods-because-private-methods-can)
So you would never really use `private` or `protected` as a security measure
against malicious plugins in C++ nor Java, and I assume C# as well.
Your best bet is to run your plugins in a separate process and expose the core
API over IPC/RPC or even web service, or run them in a
[sandbox](https://www.google.com/search?q=sandboxed+python) (as per what
@MarkHildreth pointed out). Alternatively, you can set up a certification and
signing process for your plugins so that you can review and filter out
potentially malicious plugins before they even get distributed.
**NOTE:**
You can actually achieve true encapsulation using lexical closures:
def Foo(param):
param = [param] # because `nonlocal` was introduced only in 3.x
class _Foo(object):
@property
def param(self):
return param[0]
@param.setter
def param(self, val):
param[0] = val
return _Foo()
foo = Foo('bar')
print foo.param # bar
foo.param = 'baz'
print foo.param # baz
# no way to access `foo._param` or anything
...but even then, the value is actually still relatively easily accessible via
reflection:
>>> foo.__class__.param.fget.__closure__[0].cell_contents[0] = 'hey'
>>> foo.param
'hey'
...and even if this weren't possible, we'd still be left with
[`ctypes`](http://docs.python.org/2/library/ctypes.html) which allows direct
memory access, bypassing any remaining cosmetic "restrictions":
import ctypes
arr = (ctypes.c_ubyte * 64).from_address(id(foo))
and now you can just assign to `arr` or read from it; although you'd have to
work hard to traverse pointers from there down to the actual memory location
where `.param` is stored, but it proves the point.
|
Setting python path for WinPython to use f2py
Question: I installed the Winpython distribution on my copy of Windows 7. Launching
iPython consoles and other items from the distribution from within the folder
it copied to works fine.
I'd like to use the f2py module from numpy to be able to call Fortran
subroutines from Python. My understanding is that f2py must be called from the
command line, but the system does not seem to find f2py, returning
`ImportError: no module named site` when I call it either with or without
flags. This same error is returned when I try to run python itself from the
command line.
When I manually navigate to the Winpython directory (e.g.
`C:\Users\AGK\WinPython-32bit-2.7.5.3\python-2.7.5`) and call `f2py -c --help-
fcompiler` to see if f2py is found there, I receive the following error
Traceback (most recent call last):
File ".\lib\site.py", line 538, in main
main()
File ".\lib\site.py", line 530, in main
known_paths = addusersitepackages(known_paths)
File ".\lib\site.py", line 266, in addusersitepackages
user_site = getusersitepackages()
File ".\lib\site.py", line 241, in getusersitepackages
user_base = getuserbase() # this will also set USER_BASE
File ".\lib\site.py", line 231, in getuserbase
USER_BASE = get_config_var('userbase')
File "C:\Users\AGK\WinPython-32bit-2.7.5.3\python-2.7.5\lib\sysconfig.py",
line 516, in get_config_var
return get_config_vars().get(name)
File "C:\Users\AGK\WinPython-32bit-2.7.5.3\python-2.7.5\lib\sysconfig.py",
line 449, in get_config_vars
import re
File "C:\Users\AGK\WinPython-32bit-2.7.5.3\python-2.7.5\lib\re.py", line 1
05, in <module>
import sre_compile
File "C:\Users\AGK\WinPython-32bit-2.7.5.3\python-2.7.5\lib\sre_parse.py"
", line 14, in <module>
import sre_parse
File "C:\Users\AGK\WinPython-32bit-2.7.5.3\python-2.7.5\lib\sre_constants.py",
line 17, in <module>
from sre_constants import *
File "C:\Users\konings\WinPython-32bit-2.7.5.3\pyt
py", line 18, in <module>
from _sre import MAXREPEAT
ImportError: cannot import name MAXREPEAT
Could somebody explain to me what this error means and/or how to use f2py with
Winpython? Thanks!
Answer: You can set your environment variable `PYTHONPATH` pointing to the folder
where these modules are. This should solve the `ImportError`s.
|
Unit test in aptana studio 3
Question: How do you run a Unit test on your class creation in aptana studio 3 on a
python format class. I am wondering if I am supposed to add something to my
code or is there a function in aptana studio that does it for you.
Answer: Aptana Studio does not have a special test mode like PyCharm does, if you want
to run unit-tests, you will simply need to create a `unittest` using Python's
`unittest` module. So, for example:
import unittest
class MyTestCase(unittest.TestCase):
def test_something(self):
self.assertEqual(True, False)
if __name__ == '__main__':
unittest.main()
And now, simply run this script.
|
Regular Expressions using Substitution to convert numbers
Question: I'm a Python beginner, so keep in mind my regex skills are level -122.
I need to convert a string with text containing `file1` to `file01`, but not
convert `file10` to `file010`.
My program is wrong, but this is the closest I can get, I've tried dozens of
combinations but I can't get close:
import re
txt = 'file8, file9, file10'
pat = r"[0-9]"
regexp = re.compile(pat)
print(regexp.sub(r"0\d", txt))
Can someone tell me what's wrong with my pattern and substitution and give me
some suggestions?
Answer: You could capture the number and check the length before adding 0, but you
might be able to use this instead:
import re
txt = 'file8, file9, file10'
pat = r"(?<!\d)(\d)(?=,|$)"
regexp = re.compile(pat)
print(regexp.sub(r"0\1", txt))
[regex101 demo](http://regex101.com/r/bA3xC6)
`(?<! ... )` is called a negative lookbehind. This prevents (negative) a match
if the pattern after it has the pattern in the negative lookbehind matches.
For example, `(?<!a)b` will match all `b` in a string, except if it has an `a`
before it, meaning `bb`, `cb` matches, but `ab` doesn't match. `(?<!\d)(\d)`
thus matches a digit, unless it has another digit before it.
`(\d)` is a single digit, enclosed in a capture group, denoted by simple
parentheses. The captured group gets stored in the first capture group.
`(?= ... )` is a positive lookahead. This matches _only_ if the pattern inside
the positive lookahead matches after the pattern before this positive
lookahead. In other words, `a(?=b)` will match all `a` in a string only if
there's a `b` after it. `ab` matches, but `ac` or `aa` don't.
`(?=,|$)` is a positive lookahead containing `,|$` meaning either a comma, or
the end of the string.
`(?<!\d)(\d)(?=,|$)` thus matches any digit, as long as there's no digit
before it and there's a comma after it, or if that digit is at the end of the
string.
|
twisted reactor.spawnProcess get stdout w/o bufffering on windows
Question: I'm running an external process and I need to get the stdout immediately so I
can push it to a textview, on GNU/Linux I can use "usePTY=True" to get the
stdout by line, unfortunately usePTY is not available on windows.
I'm fairly new to twisted, is there a way to achieve the same result on
Windows with some twisted (or python maybe) magic stuff?
Answer: > on GNU/Linux I can use "usePTY=True" to get the stdout by line
Sort of! What `usePTY=True` actually does is create a PTY (a "pseudo-terminal" - the thing you always get when you log in to a shell on GNU/Linux unless you have a _real_ terminal which no one does anymore :) instead of a boring old pipe. A PTY is a lot like a pipe but it has some extra features - but more importantly for you, a PTY is strongly associated with interactive sessions (ie, a _user_) whereas a pipe is pretty strongly associated with programmatic uses (think `foo | bar` \- no user ever sees the output of `foo`).
This means that people tend to use existence of a PTY as stdout as a signal
that they should produce output in a timely manner - because a human is
waiting to see it. On the flip side, the existence of a regular old pipe as
stdout is taken as a signal that another program is consuming the output and
they should instead produce output in the most _efficient_ way possible.
What this **tends** to mean in practice is that if a program has a PTY then
_it_ will line buffer its output and if it has a pipe then _it_ will "block"
buffer its output (usually gather up about 4kB of data before writing any of
it) - because line buffering is less efficient.
The thing to note here is that it is the _program you are running_ that does
this buffering. Whether you pass `usePTY=True` or `usePTY=False` makes no
direct difference to that buffering: it is just a hint to the program you are
running what kind of output buffering it should do.
This means that you might run programs that block buffer even if you pass
`usePTY=True` and vice versa.
However... Windows doesn't have PTYs. So programs on Windows can't consider
PTYs as a hint for how to buffer their output.
I don't actually know if there is another hint that it is conventional for
programs to respect on Windows. I've never come across one, at least.
If you're lucky, then the program you're running will have _some_ way for you
to request line-buffered output. If you're running Python, then it does - the
`PYTHONUNBUFFERED` environment variable controls this, as does the `-u`
command line option (and I think they both work on Windows).
Incidentally, if you plan to pass binary data between the two processes, then
you probably also want to put stdio into binary mode in the child process as
well:
import os, sys, mscvrt
msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
|
Getting error when running the Django server on my Mac 10.8.5
Question: I am trying to setup Python/Django/Mysql on my Mac but I keep getting the
following error when I run this command in terminal
Python manage.py runserver
The error I get is
Marks-MacBook-Air:FirstBlog mmillar$ python manage.py runserver
Validating models...
Unhandled exception in thread started by <bound method Command.inner_run of <django.contrib.staticfiles.management.commands.runserver.Command object at 0x1017c2b10>>
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 92, in inner_run
self.validate(display_num_errors=True)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 280, in validate
num_errors = get_validation_errors(s, app)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/validation.py", line 35, in get_validation_errors
for (app_name, error) in get_app_errors().items():
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/loading.py", line 166, in get_app_errors
self._populate()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/loading.py", line 72, in _populate
self.load_app(app_name, True)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/loading.py", line 96, in load_app
models = import_module('.models', app_name)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module
__import__(name)
File "/Users/mmillar/PycharmProjects/FirstBlog/blog/models.py", line 5, in <module>
class post(models.Model):
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.py", line 145, in __new__
new_class.add_to_class(obj_name, obj)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.py", line 265, in add_to_class
value.contribute_to_class(cls, name)
TypeError: Error when calling the metaclass bases
unbound method contribute_to_class() must be called with TextField instance as first argument (got ModelBase instance instead)
* * *
**models.py**
from django.db import models
# Create your models here.
class post(models.Model):
author = models.CharField(max_length=30)
title = models.CharField(max_length=100)
bodytext = models.TextField
timestamp = models.DateTimeField
Answer: I think you did something like that:
wrong:
class Foo(models.Model):
bar = models.TextField
correct:
class Foo(models.Model):
bar = models.TextField()
Thus you try to validate with a class instead of a class instance.
|
How to create Excel or Windows Msg Box using COM in Python?
Question: Is there a way to get pywin32 to generate a VBA-style MsgBox in Excel, if not,
perhaps the Windows equivalent?
I tried:
from win32com.client import Dispatch
excel = Dispatch('Excel.Application')
excel.MsgBox('foo')
but it gives the error below:
AttributeError: Excel.Application.MsgBox
Answer: Hi you can use win32api:
import win32api
from win32con import MB_SYSTEMMODAL
response = win32api.MessageBox(0, "Did you hear the Buzzer?", "Buzzer Test", 4, MB_SYSTEMMODAL)
MB_SYSTEMMODAL is used for telling the system to show a message above all
other applications.
|
Input to process using Python
Question: I have a command (Say foo) that I normally run from terminal like so:
user@computer$ foo
enter the string: *(here I enter some string)*
RESULT OF THE COMMAND WITH THE GIVEN INPUT
I know beforehand what input I need to give. So, how do I automate the call
using this python code:
from subprocess import call
call(['foo'])
How do I automate the input to foo ?
Answer: You can check out the third-party [pexpect](http://www.noah.org/wiki/pexpect)
module ([Here is the API](http://pexpect.sourceforge.net/pexpect.html)):
import pexpect
child = pexpect.spawn('foo')
child.expect('enter the string:')
child.sendline('STRING YOU KNOW TO ENTER')
child.close() # End Communication
|
Scrape internal links with Beautiful soup
Question: I have written a python code to fetch the web-page corresponding to a given
url, and parses all the links on that page into a repository of links. Next,
it fetches the contents of any of the url from the repository just created,
parses the links from this new content into the repository and continues this
process for all links in the repository until stopped or after a given number
of links are fetched.
Here code:
import BeautifulSoup
import urllib2
import itertools
import random
class Crawler(object):
"""docstring for Crawler"""
def __init__(self):
self.soup = None # Beautiful Soup object
self.current_page = "http://www.python.org/" # Current page's address
self.links = set() # Queue with every links fetched
self.visited_links = set()
self.counter = 0 # Simple counter for debug purpose
def open(self):
# Open url
print self.counter , ":", self.current_page
res = urllib2.urlopen(self.current_page)
html_code = res.read()
self.visited_links.add(self.current_page)
# Fetch every links
self.soup = BeautifulSoup.BeautifulSoup(html_code)
page_links = []
try :
page_links = itertools.ifilter( # Only deal with absolute links
lambda href: 'http://' in href,
( a.get('href') for a in self.soup.findAll('a') ) )
except Exception: # Magnificent exception handling
pass
# Update links
self.links = self.links.union( set(page_links) )
# Choose a random url from non-visited set
self.current_page = random.sample( self.links.difference(self.visited_links),1)[0]
self.counter+=1
def run(self):
# Crawl 3 webpages (or stop if all url has been fetched)
while len(self.visited_links) < 3 or (self.visited_links == self.links):
self.open()
for link in self.links:
print link
if __name__ == '__main__':
C = Crawler()
C.run()
This code does not fetch internal links (only absolute formed hyperlinks)
**How to fetch Internal links that starts with '/' or '#' or '.'**
Answer: Well, your code kind of already tells you what's going on. In your lambda you
are only grabbing absolute links that start with http:// (which you are not
grabbing https FWIW). You should grab all of the links and check to see if
they start with http+ or not. If they don't, then they are a relative link,
and since you know what the `current_page` is then you can use that to create
an absolute link.
Here's a modification to your code. Excuse my Python as it's a little rusty,
but I ran it and it worked in Python 2.7 for me. You'll want to clean it up
and add some edge/error detection, but you get the gist:
#!/usr/bin/python
from bs4 import BeautifulSoup
import urllib2
import itertools
import random
import urlparse
class Crawler(object):
"""docstring for Crawler"""
def __init__(self):
self.soup = None # Beautiful Soup object
self.current_page = "http://www.python.org/" # Current page's address
self.links = set() # Queue with every links fetched
self.visited_links = set()
self.counter = 0 # Simple counter for debug purpose
def open(self):
# Open url
print self.counter , ":", self.current_page
res = urllib2.urlopen(self.current_page)
html_code = res.read()
self.visited_links.add(self.current_page)
# Fetch every links
self.soup = BeautifulSoup(html_code)
page_links = []
try :
for link in [h.get('href') for h in self.soup.find_all('a')]:
print "Found link: '" + link + "'"
if link.startswith('http'):
page_links.append(link)
print "Adding link" + link + "\n"
elif link.startswith('/'):
parts = urlparse.urlparse(self.current_page)
page_links.append(parts.scheme + '://' + parts.netloc + link)
print "Adding link " + parts.scheme + '://' + parts.netloc + link + "\n"
else:
page_links.append(self.current_page+link)
print "Adding link " + self.current_page+link + "\n"
except Exception, ex: # Magnificent exception handling
print ex
# Update links
self.links = self.links.union( set(page_links) )
# Choose a random url from non-visited set
self.current_page = random.sample( self.links.difference(self.visited_links),1)[0]
self.counter+=1
def run(self):
# Crawl 3 webpages (or stop if all url has been fetched)
while len(self.visited_links) < 3 or (self.visited_links == self.links):
self.open()
for link in self.links:
print link
if __name__ == '__main__':
C = Crawler()
C.run()
|
Python TypeError: iteration over non-sequence on simple list
Question:
import os
test = os.system("ls /etc/init.d/ | grep jboss- | grep -vw jboss-")
for row in test:
print row
For some reason this gives the TypeError: iteration over non-sequence error on
this.
When I do a print test without the for loop, it gives a list of the jboss
instances, plus a "0" at the bottom.. The heck?
Answer: `os.system()` returns the _exit code_ of the process, _not_ the result of the
`grep` commands. This is always an integer. In the meantime, the output of the
process itself is not redirected, so it writes to `stdout` directly (bypassing
Python).
You cannot iterate over over an integer.
You should use the [`subprocess.check_output()`
function](http://docs.python.org/2/library/subprocess.html#subprocess.check_output)
instead if you wanted to retrieve the stdout output of the command.
In this case, you'd be better off using `os.listdir()` and code the whole
search in Python instead:
for filename in os.listdir('/etc/init.d/'):
if 'jboss-' in filename and not filename.startswith('jboss-'):
print filename
I've interpreted the `grep -vw jboss-` command as filtering out filenames that
_start_ with `jboss`; adjust as needed.
|
Deduction of Integer Math (Order of Operations)
Question: I'm working in Python at the moment, and I'm coming to a problem I don't know
where to grab straws. Forgive me if this is covered in some initial Algorithm
CS class somewhere, my background is really in Economics. I'm working with
financial data, and I know the output and the inputs, I just don't know how to
get to the order of operations.
For instance, I have a final price to earnings ratio of 2, but inputs of 10
(price) and 5 (earnings). Just looking at this, I know 10/5 would be
equivalent to 2. However, the problem is the order of operations .... this
could be either addition, multiplication, division and square roots.
This part seems doable if I just had
inputs = [10,5]
output = 2
def deduction_int(inputs, output):
initial_output = 0
while initial_output != output:
try adding, try subtracting (inverse), try dividing(inverse)
prints 'yay' when its got itself figured out or if there is an answer
The above code seems obvious and quick, however, when you add 3 variables to
it ....
inputs : 10, 5, 7 output : 2.14
and situations such as (10 + 5) / 7 = 2.14.
I'm stuck with situations where numbers might be run with a different order.
For instance 10+5 runs before dividing by 7. Is this a common algorithm type
of problem? If so, where exactly do I look for some textbook description (name
of the algorithm, textbook)?
Thanks!
Answer: Here is a brute-force algorithm.
from __future__ import division
import itertools as IT
import operator
opmap = {operator.add: '+',
operator.mul: '*',
operator.truediv: '/'}
operators = opmap.keys()
def deduction_int(inputs, output):
iternums = IT.permutations(inputs, len(inputs))
iterops = IT.product(operators, repeat=len(inputs)-1)
for nums, ops in IT.product(iternums, iterops):
for result, rstr in combine(nums, ops):
if near(result, output, atol=1e-3):
return rstr
def combine(nums, ops, astr=''):
a = nums[0]
astr = astr if astr else str(a)
try:
op = ops[0]
except IndexError:
return [(a, astr)]
# combine a op (...)
result = []
for partial_val, partial_str in combine(nums[1:], ops[1:]):
r = op(a, partial_val)
if len(nums[1:]) > 1:
rstr = '{}{}({})'.format(astr, opmap[op], partial_str)
else:
rstr = '{}{}{}'.format(astr, opmap[op], partial_str)
assert near(eval(rstr), r)
result.append((r, rstr))
# combine (a op ...)
b = nums[1]
astr = '({}{}{})'.format(astr,opmap[op], b)
for partial_val, partial_str in combine((op(a, b),)+nums[2:], ops[1:],
astr):
assert near(eval(partial_str), partial_val)
result.append((partial_val, partial_str))
return result
def near(a, b, rtol=1e-5, atol=1e-8):
return abs(a - b) < (atol + rtol * abs(b))
def report(inputs, output):
rstr = deduction_int(inputs, output)
return '{} = {}'.format(rstr, output)
print(report([10,5,7], (10+5)/7))
print(report([1,2,3,4], 3/7.))
print(report([1,2,3,4,5], (1+(2/3)*(4-5))))
yields
(10+5)/7 = 2.14285714286
(1+2)/(3+4) = 0.428571428571
(1+5)/((2+4)*3) = 0.333333333333
* * *
The main idea is to simply enumerate all orderings of the input values, and
all orderings of the operators. For example,
In [19]: list(IT.permutations([10,5,7], 3))
Out[19]: [(10, 5, 7), (10, 7, 5), (5, 10, 7), (5, 7, 10), (7, 10, 5), (7, 5, 10)]
Then you pair each ordering of the input values with each ordering of the
operators:
In [38]: list(IT.product(iternums, iterops))
Out[38]:
[((10, 5, 7), (<built-in function add>, <built-in function mul>)),
((10, 5, 7), (<built-in function add>, <built-in function truediv>)),
((10, 5, 7), (<built-in function mul>, <built-in function add>)),
((10, 5, 7), (<built-in function mul>, <built-in function truediv>)),
...
The `combine` function takes an ordering of the nums and an ordering of the
ops, and enumerates all possible groupings of the nums and ops: In [65]:
combine((10, 5, 7), (operator.add, operator.mul))
Out[65]: [(45, '10+(5*7)'), (45, '10+((5*7))'), (105, '(10+5)*7'), (105, '((10+5)*7)')]
It returns a list of tuples. Each tuple is a 2-tuple consisting of a numerical
value and the string representation, `rstr`, of the grouped operations which
evaluates to that value.
So, you just loop over every possibility and return the `rstr` which, when
evaluated, produces a number close to `output`.
for nums, ops in IT.product(iternums, iterops):
for result, rstr in combine(nums, ops):
if near(result, output, atol=1e-3):
return rstr
* * *
**Some useful references:**
* [itertools.permutations](http://docs.python.org/2/library/itertools.html#itertools.permutations)
* [itertools.product](http://docs.python.org/2/library/itertools.html#itertools.product)
* [itertools.izip](http://docs.python.org/2/library/itertools.html#itertools.izip)
|
Follow the keyboard selection in Ubuntu preferably by Python
Question: I am doing automation of my application. To do this at one point I need to
move my mouse to selected item. I shall select the item with my keyboard and
mouse will move accordingly to that point. Is there any code for doing this in
Ubuntu 12.04 and 12.10. I am using Python for automation.
Answer: Assuming you:
* Know the coordinates of the "item" you've selected in your application
* Are using Ubuntu
You can do this inside your python script:
from subprocess import call
call(["xdotool", "mousemove", "300", "500"])
You might have to install xdotool if you don't have it installed:
sudo apt-get install xdotool
You may want to `man xdotool` to get more information on it - it's pretty
awesome for automating keyboard/mouse events!
|
Read value from web page using python
Question: I am trying to read a value in a html page into a variable in a python script.
I have already figured out a way of downloading the page to a local file using
urllib and could extract the value with a bash script but would like to try it
in Python.
import urllib
urllib.urlretrieve('http://url.com', 'page.htm')
The page has this in it:
<div name="mainbody" style="font-size: x-large;margin:auto;width:33;">
<b><a href="w.cgi?hsn=10543">Plateau (19:01)</a></b>
<br/> Wired: 17.4
<br/>P10 Chard: 16.7
<br/>P1 P. Gris: 17.1
<br/>P20 Pinot Noir: 15.8-
<br/>Soil Temp : Error
<br/>Rainfall: 0.2<br/>
</div>
I need the 17.4 value from the Wired: line
Any suggestions?
Thanks
Answer: Start with not using `urlretrieve()`; you want the data, not a file.
Next, use a HTML parser.
[BeautifulSoup](http://www.crummy.com/software/BeautifulSoup/bs4/doc/) is
great for extracting text from HTML.
Retrieving the page with `urllib2` would be:
from urllib2 import urlopen
response = urlopen('http://url.com/')
then read the data into BeautifulSoup:
from bs4 import BeautifulSoup
soup = BeautifulSoup(response.read(), from_encoding=response.headers.getparam('charset'))
The `from_encoding` part there will tell BeautifulSoup what encoding the web
server told you to use for the page; if the web server did not specify this
then BeautifulSoup will make an educated guess for you.
Now you can search for your data:
for line in soup.find('div', {'name': 'mainbody'}).stripped_strings:
if 'Wired:' in line:
value = float(line.partition('Wired:')[2])
print value
For your demo HTML snippet that gives:
>>> for line in soup.find('div', {'name': 'mainbody'}).stripped_strings:
... if 'Wired:' in line:
... value = float(line.partition('Wired:')[2])
... print value
...
17.4
|
my RAM gets full and PC crashes when i execute my python script .
Question: I wrote a simple script in python . It's a talking battery monitor , inspired
from IronMan Jarvis . Now the problem is that , the code runs perfectly but
the RAM keeps getting full when the code is running . Finally when the RAM
gets full , the PC crashes . What could be the problem? I dont use any new
varibles . I update the same variable by polling . This is my code-
# Get power status of the system using ctypes to call GetSystemPowerStatus
import ctypes
from ctypes import wintypes
import speech
def startmonitor():
class SYSTEM_POWER_STATUS(ctypes.Structure):
_fields_ = [
('ACLineStatus', wintypes.BYTE),
('BatteryFlag', wintypes.BYTE),
('BatteryLifePercent', wintypes.BYTE),
('Reserved1', wintypes.BYTE),
('BatteryLifeTime', wintypes.DWORD),
('BatteryFullLifeTime', wintypes.DWORD),
]
SYSTEM_POWER_STATUS_P = ctypes.POINTER(SYSTEM_POWER_STATUS)
GetSystemPowerStatus = ctypes.windll.kernel32.GetSystemPowerStatus
GetSystemPowerStatus.argtypes = [SYSTEM_POWER_STATUS_P]
GetSystemPowerStatus.restype = wintypes.BOOL
status = SYSTEM_POWER_STATUS() #define an object of the class SYSTEM_POWER_STATUS
if not GetSystemPowerStatus(ctypes.pointer(status)):
raise ctypes.WinError()
return status
x=0 #counting variable
def setflag0():
for x in range(7):
flag[x]=0
return flag
def setxval():
if(status.BatteryLifePercent==100):
x=0
elif(status.BatteryLifePercent<100 and status.BatteryLifePercent>30):
x=1
elif(status.BatteryLifePercent<=30 and status.BatteryLifePercent>15):
x=2
elif(status.BatteryLifePercent<=15 and status.BatteryLifePercent>5):
x=3
elif(status.BatteryLifePercent<=5):
x=4
return x
flag=[0,0,0,0,0,0,0]
speech.say("This is the talking battery monitor version 1.0")
while(1) :
status=startmonitor()
bat=setxval()
if(bat!=0 and status.ACLineStatus==1 and flag[1]!=1):
speech.say("All power systems being charged sir ! ")
flag=setflag0()
flag[1]=1
elif(bat==0 and flag[6]!=1):
if(status.ACLineStatus==1):
speech.say("Battery : one hundred percent charged")
elif(status.ACLineStatus==0):
speech.say("Sir , You have full battery power")
flag=setflag0()
flag[6]=1
elif(bat==1 and status.ACLineStatus==0 and flag[2]!=1):
speech.say("Battery Level : ")
speech.say(status.BatteryLifePercent)
speech.say("percent")
flag=setflag0()
flag[2]=1
elif(bat==2 and flag[3]!=1 and status.ACLineStatus==0):
speech.say("Sir, i'm running low on battery . Please put me on charge !" )
flag=setflag0()
flag[3]=1
elif(bat==3 and flag[4]!=1 and status.ACLineStatus==0):
speech.say("Sir, you're now running on emergency backup power")
flag=setflag0()
flag[4]=1
elif(bat==4 and flag[5]!=1 and status.ACLineStatus==0):
speech.say(" Alert ! Power critical Sir, I might turn off in ")
speech.say(status.BatteryLifeTime/1000000)
speech.say("minutes")
flag=setflag0()
flag[5]=1
Answer: Somewhere in the loop a function is using memory.
It might be that the system call SYSTEM_POWER_STATUS is using memory. Is it
possible to call
status=startmonitor()
before the while loop?
Otherwise start removing code (even though it breaks the functionality
temporarily) to find out which part uses memory and try to find an alternative
for that part.
|
How to set an optional argument from python in terminal?
Question: I have a program that takes one input but can also take another optional
argument if the user wants. How can I implement this optional argument?
I am importing sys library to get the first arguement like this
word_input = sys.argv[1]
num_input = sys.argv[2] // I want to make this optional
Answer: Test for the length; `sys.argv` is just a list, really:
num_input = sys.argv[2] if len(sys.argv) > 2 else None
|
Problems using Metakit for Python on Windows
Question: I'm having problems trying to use Metakit for Python on Windows. It always
report this error:
Traceback (most recent call last):
File "<pyshell#86>", line 1, in <module>
import metakit
File "C:\Python27\lib\site-packages\metakit.py", line 22, in <module>
from Mk4py import *
ImportError: No module named Mk4py
I've already:
* Downloaded metakit.py and Mk4py.dll from <http://equi4.com/pub/mk/> (official release)
* Copied metatkit.py to C:\Python27\lib\site-packages\
* Copied Mk4py.dll to C:\Python27\DLLs\
I have installed Python 2.7.5 win32 version
Any idea to solve this problem?
Answer: I also had the same problem and couldn't get the system to work with the
provided dlls. I also tried compiling metakit from source to make it work and
installing it from an the official source via egg, which failed in the same
way (as it compiles from source).
Using my older windows XP machine with visual studio 2002 I managed to build
it from source and install it with just a minor change of the setup script
(changing every instance of msvc60 to msvc70 in the setup script). However,
copying those files to my windows 8 machine still failed, and even copying
what appeared to be the changes were unsuccessful.
In the end I copied my entire python directory from the xp machine to the
windows 8 machine and now it is working without issues.
Obviously i could provide my dlls but I doubt they would be any more
successful than the provided ones.
My next step is to reduce my reliance on having to use metakit as it seems
very poorly supported.
|
Integer Gui input for button command in Python 2.7
Question: I have a very simple GUI I am trying to make in which I have a single entry,
and a single button. I would like to enter a number in the entry, and then use
that number as a variable in the command that my button initiates.
For example, if you enter a 2 and my command was to compute 2+emtry, selecting
the button would yield a 4.
I have 2 problems:
1. How to convert the entry into an integer?
2. How to use that integer in the command my button calls.
I am very new to Python. Here is my code:
from Tkinter import *
import tkMessageBox
import Tkinter
root = Tkinter.Tk()
root.title("Title")
root.geometry("150x150")
Lbl1 = Label(root, text="Input a number here:")
Lbl1.pack(side=TOP,padx=5,pady=5)
Entry1 = Entry(root, bd =1)
Entry1.pack(side=TOP,padx=5,pady=5)
def PrintCommand():
print('I want the number from the entry here')
bttn1 = Tkinter.Button(root, text ="print command", command = PrintCommand)
bttn1.pack(side = TOP,padx=10,pady=20)
root.mainloop()
Answer: To get the value, use the `get` method on the entry. To convert it to an
integer you can use the python `int` function:
def PrintCommand():
the_number = int(Entry1.get())
print(the_number)
|
How to run two loops at the same time in python
Question: How can i run a loop within a loop in python to make points in a simple word
game
import random
WORDS = ("python", "jumble", "easy", "difficult", "answer", "xylophone", "truck", "doom", "mayonase", "flying", "magic", "mine", "bugle")
play = "Yes"
points = 0
ask = ('Yes')
word = random.choice(WORDS)
while play == "Yes":
hint = word
correct = word
jumble = ""
while word:
position = random.randrange(len(word))
jumble += word[position]
word = word[:position] + word[(position + 1):]
print(
"""
Welcome to Word Jumble!
Unscramble the letters to make a word.
(Press the enter key at the prompt to quit.)
"""
)
print("The jumble is:", jumble)
guess = input("\nYour guess: ")
while guess != correct and guess != "":
print("Sorry, that's not it.")
guess = input("Your guess: ")
print("Do you want a hint")
if ask == "yes":
print(word)
points - 10
print(points)
if guess == correct:
print("That's it! You guessed it!\n")
play = input("Do you want to play again")
points + 100
print(points)
print("Thanks for playing.")
input("\n\nPress the enter key to exit.")
is all the code i have im trying to add a point system into it. The problem im
trying to do is "Improve “Word Jumble” so that each word is paired with a
hint. The player should be able to see the hint if he or she is stuck. Add a
scoring system that rewards players who solve a jumble without asking for the
hint."
Answer: Came up with something like this... needs a lot of work, but it will set you
on the right track (I hope so!!)
Here's the modified code:
import random
WORDS = ("python", "jumble", "easy", "difficult", "answer", "xylophone", "truck", "doom", "mayonase", "flying", "magic", "mine", "bugle")
play = "Yes"
points = 0
ask = ('Yes')
word = random.choice(WORDS)
while play == "Yes":
next_hint = 4
hint = "{}...".format(word[0:next_hint])
correct = word
jumble = ""
while word:
position = random.randrange(len(word))
jumble += word[position]
word = word[:position] + word[(position + 1):]
print(
"""
Welcome to Word Jumble!
Unscramble the letters to make a word.
(Press the enter key at the prompt to quit.)
"""
)
print("The jumble is:", jumble)
guess = input("\nYour guess: ")
while guess != correct and guess != "":
print("Sorry, that's not it.")
if hint != word:
ask = input("Do you want a hint? yes / no: ")
if ask in ("yes", "y", "yeah"):
print(hint)
next_hint += 1
hint = "{}...".format(correct[0:next_hint])
points -= 10
print("You lose 10 points!")
guess = input("Your guess: ")
if guess == correct:
print("That's it! You guessed it!\n")
play = input("Do you want to play again? yes/no: ")
points += 100
print("You earn {} points!".format(points))
print("Thanks for playing.")
input("\n\nPress the enter key to exit.")
I added hints that will gradually show the word and fixed the point system (Or
at least it takes into account how many hints you used). The problem is, I
always show at least 4 characters of the string and some words are that short
(you'll have to fix that) Hope it helps!!!
|
Select all in a tkinter Listbox
Question: I am creating a `Listbox` using Tkinter and Python. I want to make a Button
for `select all`, but I can't find any info regarding selecting elements using
code.
self.l = Listbox(self, height=12, selectmode=MULTIPLE)
self.selectAll=Button(self, text="select all",
command=self.selectAllCallback())
def selectAllCallback(self)
# What to do here
Answer: You can use
[`selection_set`](http://effbot.org/tkinterbook/listbox.htm#Tkinter.Listbox.selection_set-
method) (or `select_set`) method with `0` and `END` as arguments.
For example, try following code:
from Tkinter import *
def select_all():
lb.select_set(0, END)
root = Tk()
lb = Listbox(root, selectmode=MULTIPLE)
for i in range(10): lb.insert(END, i)
lb.pack()
Button(root, text='select all', command=select_all).pack()
root.mainloop()
In the following statement, you are calling `self.selectAllCallback`, not bind
it with button click. It is called before the button is generated.
self.selectAll=Button(self,text="select all", command=self.selectAllCallback())
^^
It should be:
self.selectAll=Button(self, text="select all", command=self.selectAllCallback)
|
Flexible UNIX command line interface with Python
Question: I was wondering how to create a flexible CLI interface with Python. So far I
have come up with the following:
$ cat cat.py
#!/usr/bin/env python
from sys import stdin
from fileinput import input
from argparse import ArgumentParser, FileType
def main(args):
for line in input():
print line.strip()
if __name__ == "__main__":
parser = ArgumentParser()
parser.add_argument('FILE', nargs='?', type=FileType('r'), default=stdin)
main(parser.parse_args())
This handles both stdin and file input:
$ echo 'stdin test' | ./cat.py
stdin test
$ ./cat.py file
file test
The problem is it doesn't handle multiple input or no input the way I would
like:
$ ./cat.py file file
usage: cat.py [-h] [FILE]
cat.py: error: unrecognized arguments: file
$ ./cat.py
For multiple inputs it should `cat` the file multiple times and for no input
input should ideally have same the behaviour as `-h`:
$ ./cat.py -h
usage: cat.py [-h] [FILE]
positional arguments:
FILE
optional arguments:
-h, --help show this help message and exit
Any ideas on creating a flexible CLI interface with Python?
Answer: Use [`nargs='*'`](http://docs.python.org/2/library/argparse.html#nargs) to
allow for 0 or more arguments:
if __name__ == "__main__":
parser = ArgumentParser()
parser.add_argument('FILE', nargs='*', type=FileType('r'), default=stdin)
main(parser.parse_args())
The help output now is:
$ bin/python cat.py -h
usage: cat.py [-h] [FILE [FILE ...]]
positional arguments:
FILE
optional arguments:
-h, --help show this help message and exit
and when no arguments are given, `stdout` is used.
If you want to require at least one `FILE` argument, use `nargs='+'` instead,
but then the default is ignored, so you may as well drop that:
if __name__ == "__main__":
parser = ArgumentParser()
parser.add_argument('FILE', nargs='+', type=FileType('r'))
main(parser.parse_args())
Now not specifying a command-line argument gives:
$ bin/python cat.py
usage: cat.py [-h] FILE [FILE ...]
cat.py: error: too few arguments
You can always specify `stdin` still by passing in `-` as an argument:
$ echo 'hello world!' | bin/python cat.py -
hello world!
|
Using Counter() in Python to build histogram?
Question: I saw on another question that I could use `Counter()` to count the number of
occurrences in a set of strings. So if I have `['A','B','A','C','A','A']` I
get `Counter({'A':3,'B':1,'C':1})`. But now, how can I use that information to
build a histogram for example?
Answer: For your data it is probably better to use a barchart instead of a histogram.
Check out this code:
from collections import Counter
import numpy as np
import matplotlib.pyplot as plt
labels, values = zip(*Counter(['A','B','A','C','A','A']).items())
indexes = np.arange(len(labels))
width = 1
plt.bar(indexes, values, width)
plt.xticks(indexes + width * 0.5, labels)
plt.show()
Result: 
|
How to use the resource module to measure the running time of a function?
Question: I want to measure the CPU running time and wall clock running time of
functions using Python code.
The resource module was suggested here: [How to measure CPU running time and
wall clock running time of a function, separately, as Python code (not from
terminal)?](http://stackoverflow.com/q/19204618/1690799)
Here is the module documentation:
<http://docs.python.org/2/library/resource.html>
The problem is that:
1) I can't figure out how to use it to measure the running time of a function.
2) I don't know how to extract that information from the object returned.
How do I do this?
Answer: Just call
[`getrusage`](http://docs.python.org/2/library/resource.html#resource.getrusage)
before and after executing the function, subtract the fields you care about,
and you're done. Since `resource` doesn't do wall time, you'll need to use a
separate function for that.
You can wrap that up in a helper function, or even a decorator, like this:
import datetime
import functools
import resource
import sys
def timed(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
r0 = resource.getrusage(resource.RUSAGE_SELF)
t0 = datetime.datetime.now()
retval = func(*args, **kwargs)
r = resource.getrusage(resource.RUSAGE_SELF)
t = datetime.datetime.now()
sys.stderr.write('{}: utime {} stime {} wall: {}\n'.format(
func.__name__,
datetime.timedelta(seconds=r.ru_utime-r0.ru_utime),
datetime.timedelta(seconds=r.ru_stime-r0.ru_stime),
t-t0))
return retval
return wrapper
@timed
def myfunc(i):
for _ in range(100000000):
pass
return i*2
print(myfunc(2))
This will print out something like:
myfunc: utime 0:00:03.261688 stime 0:00:00.805324 wall 0:00:04.067109
4
If you want more than a couple fields, you probably want to subtract all of
the members of the rusage results, but since these are all int or float,
that's easy:
rdiff = resource.struct_rusage(f1-f0 for f0, f1 in zip(r0, r))
sys.stderr.write('{}: utime {} maxrss {} nsignals {} etc.\n'.format(
datetime.timedelta(seconds=rdiff.r_utime),
rdiff.ru_maxrss,
rdiff.ru_nsignals))
|
Does Queue.get block main?
Question: I know that `Queue.get()` method in python is a blocking function. I need to
know if I implemented this function inside the main, waiting for an object set
by a thread, does this means that all the main will be blocked.
For instance, if the main contains functions for transmitter and receiver,
will the two work together or not?
Answer: Yes -- if you call `some_queue.get()` within either the thread or the `main`
function, the program will block there until some object as passed through the
queue.
* * *
However, it is possible to use queues so that they [don't
block](http://docs.python.org/2/library/queue.html#Queue.Queue.get), or so
that they have a timeout of some kind:
import Queue
while True:
try:
data = some_queue.get(False)
# If `False`, the program is not blocked. `Queue.Empty` is thrown if
# the queue is empty
except Queue.Empty:
data = None
try:
data2 = some_queue.get(True, 3)
# Waits for 3 seconds, otherwise throws `Queue.Empty`
except Queue.Empty:
data = None
You can do the same for `some_queue.put` \-- either do `some_queue.put(item,
False)` for non-blocking queues, or `some_queue.put(item, True, 3)` for
timeouts. If your queue has a size limit, it will throw a `Queue.Full`
exception if there is no more room left to append a new item.
|
Why calculations of eigenvectors of a 2 by 2 matrix with numpy crashes my Python session?
Question: I try to do the following:
import numpy as np
from numpy import linalg as la
w, v = la.eig(np.array([[1, -1], [1, 1]]))
As a result I have a crash of the python session with the following message:
Illegal instruction (core dumped)
I tried to use scipy instead of numpy. The result is the same.
Answer: I suspect that there is a problem with your installation of python/numpy/scipy
as when I try it I have no problems.
Python 2.7.4 (default, Sep 26 2013, 03:20:26)
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy as np
>>> from numpy import linalg as la
>>> w, v = la.eig(np.array([[1, -1], [1, 1]]))
>>> w
array([ 1.+1.j, 1.-1.j])
>>> v
array([[ 0.70710678+0.j , 0.70710678+0.j ],
[ 0.00000000-0.70710678j, 0.00000000+0.70710678j]])
>>>
I would suggest that you try a fresh installation.
|
Remote executing of program via xterm run using paramiko python ssh library
Question: Flow of the program is:
1. Connect to OpenSSH server on Linux machine using Paramiko library
2. Open X11 session
3. Run xterm executable
4. Run some other program (e.g. Firefox) by typing executable name in the terminal and running it.
I would be grateful if someone can explain how to cause some executable to run
in a terminal which was open by using the following code and provide sample
source code ([source](http://stackoverflow.com/a/19164039)):
import select
import sys
import paramiko
import Xlib.support.connect as xlib_connect
import os
import socket
import subprocess
# run xming
XmingProc = subprocess.Popen("C:/Program Files (x86)/Xming/Xming.exe :0 -clipboard -multiwindow")
ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh_client.connect(SSHServerIP, SSHServerPort, username=user, password=pwd)
transport = ssh_client.get_transport()
channelOppositeEdges = {}
local_x11_display = xlib_connect.get_display(os.environ['DISPLAY'])
inputSockets = []
def x11_handler(channel, (src_addr, src_port)):
local_x11_socket = xlib_connect.get_socket(*local_x11_display[:3])
inputSockets.append(local_x11_socket)
inputSockets.append(channel)
channelOppositeEdges[local_x11_socket.fileno()] = channel
channelOppositeEdges[channel.fileno()] = local_x11_socket
transport._queue_incoming_channel(channel)
session = transport.open_session()
inputSockets.append(session)
session.request_x11(handler = x11_handler)
session.exec_command('xterm')
transport.accept()
while not session.exit_status_ready():
readable, writable, exceptional = select.select(inputSockets,[],[])
if len(transport.server_accepts) > 0:
transport.accept()
for sock in readable:
if sock is session:
while session.recv_ready():
sys.stdout.write(session.recv(4096))
while session.recv_stderr_ready():
sys.stderr.write(session.recv_stderr(4096))
else:
try:
data = sock.recv(4096)
counterPartSocket = channelOppositeEdges[sock.fileno()]
counterPartSocket.sendall(data)
except socket.error:
inputSockets.remove(sock)
inputSockets.remove(counterPartSocket)
del channelOppositeEdges[sock.fileno()]
del channelOppositeEdges[counterPartSocket.fileno()]
sock.close()
counterPartSocket.close()
print 'Exit status:', session.recv_exit_status()
while session.recv_ready():
sys.stdout.write(session.recv(4096))
while session.recv_stderr_ready():
sys.stdout.write(session.recv_stderr(4096))
session.close()
XmingProc.terminate()
XmingProc.wait()
I was thinking about running the program in child thread, while the thread
running the xterm is waiting for the child to terminate.
Answer: Well, this is a bit of a hack, but hey.
What you can do on the remote end is the following: Inside the xterm, you run
`netcat`, listen to any data coming in on some port, and pipe whatever you get
into `bash`. It's not quite the same as typing it into xterm direclty, but
it's almost as good as typing it into bash directly, so I hope it'll get you a
bit closer to your goal. If you really want to interact with xterm directly,
you might want to [read
this](http://books.google.co.uk/books?id=t8C4pEDQ8s0C&lpg=PA294&ots=n6IT4dU7Po&dq=expect%20xterm&pg=PA293#v=onepage&q=expect%20xterm&f=false).
For example:
terminal 1:
% nc -l 3333 | bash
terminal 2 (type `echo hi` here):
% nc localhost 3333
echo hi
Now you should see `hi` pop out of the first terminal. Now try it with
`xterm&`. It worked for me.
Here's how you can automate this in Python. You may want to add some code that
enables the server to tell the client when it's ready, rather than using the
silly `time.sleep`s.
import select
import sys
import paramiko
import Xlib.support.connect as xlib_connect
import os
import socket
import subprocess
# for connecting to netcat running remotely
from multiprocessing import Process
import time
# data
import getpass
SSHServerPort=22
SSHServerIP = "localhost"
# get username/password interactively, or use some other method..
user = getpass.getuser()
pwd = getpass.getpass("enter pw for '" + user + "': ")
NETCAT_PORT = 3333
FIREFOX_CMD="/path/to/firefox &"
#FIREFOX_CMD="xclock&"#or this :)
def run_stuff_in_xterm():
time.sleep(5)
s = socket.socket(socket.AF_INET6 if ":" in SSHServerIP else socket.AF_INET, socket.SOCK_STREAM)
s.connect((SSHServerIP, NETCAT_PORT))
s.send("echo \"Hello there! Are you watching?\"\n")
s.send(FIREFOX_CMD + "\n")
time.sleep(30)
s.send("echo bye bye\n")
time.sleep(2)
s.close()
# run xming
XmingProc = subprocess.Popen("C:/Program Files (x86)/Xming/Xming.exe :0 -clipboard -multiwindow")
ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh_client.connect(SSHServerIP, SSHServerPort, username=user, password=pwd)
transport = ssh_client.get_transport()
channelOppositeEdges = {}
local_x11_display = xlib_connect.get_display(os.environ['DISPLAY'])
inputSockets = []
def x11_handler(channel, (src_addr, src_port)):
local_x11_socket = xlib_connect.get_socket(*local_x11_display[:3])
inputSockets.append(local_x11_socket)
inputSockets.append(channel)
channelOppositeEdges[local_x11_socket.fileno()] = channel
channelOppositeEdges[channel.fileno()] = local_x11_socket
transport._queue_incoming_channel(channel)
session = transport.open_session()
inputSockets.append(session)
session.request_x11(handler = x11_handler)
session.exec_command("xterm -e \"nc -l 0.0.0.0 %d | /bin/bash\"" % NETCAT_PORT)
p = Process(target=run_stuff_in_xterm)
transport.accept()
p.start()
while not session.exit_status_ready():
readable, writable, exceptional = select.select(inputSockets,[],[])
if len(transport.server_accepts) > 0:
transport.accept()
for sock in readable:
if sock is session:
while session.recv_ready():
sys.stdout.write(session.recv(4096))
while session.recv_stderr_ready():
sys.stderr.write(session.recv_stderr(4096))
else:
try:
data = sock.recv(4096)
counterPartSocket = channelOppositeEdges[sock.fileno()]
counterPartSocket.sendall(data)
except socket.error:
inputSockets.remove(sock)
inputSockets.remove(counterPartSocket)
del channelOppositeEdges[sock.fileno()]
del channelOppositeEdges[counterPartSocket.fileno()]
sock.close()
counterPartSocket.close()
p.join()
print 'Exit status:', session.recv_exit_status()
while session.recv_ready():
sys.stdout.write(session.recv(4096))
while session.recv_stderr_ready():
sys.stdout.write(session.recv_stderr(4096))
session.close()
XmingProc.terminate()
XmingProc.wait()
I tested this on a Mac, so I commented out the `XmingProc` bits and used
`/Applications/Firefox.app/Contents/MacOS/firefox` as `FIREFOX_CMD` (and
`xclock`).
The above isn't exactly a secure setup, as anyone connecting to the port at
the right time could run arbitrary code on your remote server, but it sounds
like you're planning to use this for testing purposes anyway. If you want to
improve the security, you could make netcat bind to `127.0.0.1` rather than
`0.0.0.0`, setup an ssh tunnel (run `ssh -L3333:localhost:3333
[email protected]` to tunnel all traffic received locally on port 3333
to remote-host.com:3333), and let Python connect to `("localhost", 3333)`.
Now you can combine this with [selenium](http://docs.seleniumhq.org/) for
browser automation:
Follow the instructions from [this
page](https://pypi.python.org/pypi/selenium), i.e. download the selenium
standalone server jar file, put it into `/path/to/some/place` (on the server),
and `pip install -U selenium` (again, on the server).
Next, put the following code into `selenium-example.py` in
`/path/to/some/place`:
#!/usr/bin/env python
from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.common.keys import Keys
import time
browser = webdriver.Firefox() # Get local session of firefox
browser.get("http://www.yahoo.com") # Load page
assert "Yahoo" in browser.title
elem = browser.find_element_by_name("p") # Find the query box
elem.send_keys("seleniumhq" + Keys.RETURN)
time.sleep(0.2) # Let the page load, will be added to the API
try:
browser.find_element_by_xpath("//a[contains(@href,'http://docs.seleniumhq.org')]")
except NoSuchElementException:
assert 0, "can't find seleniumhq"
browser.close()
and change the firefox command:
FIREFOX_CMD="cd /path/to/some/place && python selenium-example.py"
And watch firefox do a Yahoo search. You might also want to increase the
`time.sleep`.
If you want to run more programs, you can do things like this before or after
running firefox:
# start up xclock, wait for some time to pass, kill it.
s.send("xclock&\n")
time.sleep(1)
s.send("XCLOCK_PID=$!\n") # stash away the process id (into a bash variable)
time.sleep(30)
s.send("echo \"killing $XCLOCK_PID\"\n")
s.send("kill $XCLOCK_PID\n\n")
time.sleep(5)
If you want to do perform general X11 application control, I think you might
need to write similar "driver applications", albeit using different libraries.
You might want search for "x11 send {mouse|keyboard} events" to find more
general approaches. That brings up
[these](http://stackoverflow.com/q/6447704/1298153)
[questions](http://stackoverflow.com/q/4402216/1298153), but I'm sure there's
lots more.
If the remote end isn't responding instantaneously, you might want to sniff
your network traffic in Wireshark, and check whether or not TCP is batching up
the data, rather than sending it line by line (the `\n` seems to help here,
but I guess there's no guarantee). If this is the case, you might be [out of
luck](http://stackoverflow.com/q/10511672/1298153), but [nothing is
impossible](http://stackoverflow.com/q/13517246/1298153). I hope you don't
need to go that far though ;-)
One more note: if you need to communicate with CLI programs' STDIN/STDOUT, you
might want to look at expect scripting (e.g. using
[pexpect](http://www.noah.org/wiki/pexpect), or for simple cases you might be
able to use
subprocess.Popen.communicate](<http://docs.python.org/2/library/subprocess.html#subprocess.Popen.communicate>)).
|
Unknown command: 'collectstatic' Django 1.7
Question: I want do static files. I use Django 1.7 and Python 2.7.5 and openshift
hosting. When I try to run:
`python manage.py collectstatic`
I get:
Unknown command: 'collectstatic' Type 'manage.py help' for usage.
In my settings.py:
...
INSTALLED_APPS = (
'django.contrib.staticfiles',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'testapp',
)
TEMPLATE_CONTEXT_PROCESSORS = (
'django.core.context_processors.static',
)
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': os.environ['OPENSHIFT_APP_NAME'],
'USER': os.environ['OPENSHIFT_MYSQL_DB_USERNAME'],
'PASSWORD': os.environ['OPENSHIFT_MYSQL_DB_PASSWORD'],
'HOST': os.environ['OPENSHIFT_MYSQL_DB_HOST'],
'PORT': os.environ['OPENSHIFT_MYSQL_DB_PORT'],
}
}
STATIC_ROOT = ''
STATIC_URL = '/static/'
...
Many people had this proble. They forgot 'django.contrib.staticfiles' in
INSTALLED_APPS. But I have this setting.
Ok, I run help:
Options:
-v VERBOSITY, --verbosity=VERBOSITY
Verbosity level; 0=minimal output, 1=normal output,
2=verbose output, 3=very verbose output
--settings=SETTINGS The Python path to a settings module, e.g.
"myproject.settings.main". If this isn't provided, the
DJANGO_SETTINGS_MODULE environment variable will be
used.
--pythonpath=PYTHONPATH
A directory to add to the Python path, e.g.
"/home/djangoprojects/myproject".
--traceback Raise on exception
--no-color Don't colorize the command output.
--version show program's version number and exit
-h, --help show this help message and exit
Traceback (most recent call last):
...
File "c:\Python27\lib\os.py", line 423, in __getitem__
return self.data[key.upper()]
KeyError: 'OPENSHIFT_APP_NAME'
OPENSHIFT_APP_NAME - environment variable (link:
<https://www.openshift.com/page/openshift-environment-variables>) Can you help
me?
Answer: It looks like it can't find the environment variable `OPENSHIFT_APP_NAME`. You
should try setting it and see if that fixes the problem. Django can't import
your settings because it can't find that environment variable.
Those environment variables look like they are set by openshift. You are
probably running that collectstatic command in a shell that has not had them
set. You'll either need to set them in the shell or edit your settings.py to
be able to handle this situation. Something like this would work:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': os.environ.get('OPENSHIFT_APP_NAME', 'A sensible default'),
|
TypeError: unhashable type: 'list' (a few frames into program)
Question: So as my first project in python outside of Code Academy, I decided to make a
basic molecular dynamics simulator on pygame. It works fine for a while, but
as soon as electrons start to move too fast, and strip all the other electrons
off their atoms, I get the TypeError in the title. I have no idea where this
comes from, and only appears after the program has been running long enough
for me to mess up all the physics.
Now I know that the error is telling me that I'm trying to pass a list
somewhere I shouldn't, but I've looked over the program and can't figure out
where. The error pops up in the bit that tells electrons how to orbit their
atom `angle = findA(particles[el], particles[nuc]) + 0.001`, which is
controlled by the block of code near the end that tells the program in which
order to do physics, and the list of what each electron is meant to orbit is
controlled by another point, and so on.
So I decided just to give you all the code.
import sys, pygame, math
from pygame.locals import *
pygame.init()
sizeScreen = width, height = 1000, 700
sizeMenu = width, height = 652, 700
e = 1.6 * 10 ** -19
particles = {}
mx, my = 0, 0
selected = []
def findOrbital(el):
for a in particles:
if a != el and particles[a][4] != 'el':
if findD(particles[el], particles[a]) < 5 * 10 ** -11 and PTI[particles[a][4]][7] > len(particles[a][5]):
particles[a][5].append(el)
particles[el][5].append(a)
def searcher(List, item):
for a in List:
if a == item:
return True
return False
def moveAtEls(el, nuc):
angle = findA(particles[el], particles[nuc]) + 0.001
particles[el][0] = particles[nuc][0] + 50 * math.cos(angle)
particles[el][1] = particles[nuc][1] + 50 * math.sin(angle)
def check(each):
if particles[each][0] < 175:
particles[each][2] = -particles[each][2]
particles[each][0] = 175
elif particles[each][0] > 1000:
particles[each][2] = -particles[each][2]
particles[each][0] = 1000
if particles[each][1] < 0:
particles[each][3] = -particles[each][3]
particles[each][1] = 0
elif particles[each][1] > 700:
particles[each][3] = -particles[each][3]
particles[each][1] = 700
if particles[each][4] == 'el':
a = 'n'
findOrbital(each)
if a != 'n':
particles[each][5].append(a)
particles[a][5].append(each)
def findD(self, other):
return math.hypot((self[0] - other[0]), (self[1] - other[1])) * 0.62 * 10 ** -12
def findA(self, other):
return math.atan2((self[1] - other[1]), (self[0] - other[0]))
def move(self):
for other in particles:
if particles[other] != self and self[5] != particles[other] [5] and not searcher(self[5], other):
D = findD(self, particles[other])
if D == 0:
self[5].append(other)
particles[other][5].append(self)
break
angle = findA(self, particles[other])
F = 8987550000 * (PTI[self[4]][4] * PTI[particles[other][4]][4] * e ** 2)/D ** 2
a = int(F/PTI[self[4]][5])
ax = a * math.cos(angle)
ay = a * math.sin(angle)
self[2] += ax/(10 ** 16)
self[3] += ay/(10 ** 16)
self[0] += self[2]/(10 ** 8)
self[1] += self[3]/(10 ** 8)
pressed = ''
press = {'Katom':[2,148,2,32,0],'Knuc':[2,148,36,66,0],'Kel':[2,148,70,100,0]}
PTI = {'el':[0, 0, 0, 0, -1, 9.11 * 10 ** -31, pygame.image.load("electron.png"), 2],
'HNuc' : [185, 214, 8, 37, 1, 1.7 * 10 ** -27, pygame.image.load("nuc/HNuc.png"), 2, 1],
'HeNuc': [586, 613, 8, 37, 2, 6.6 * 10 ** -27, pygame.image.load("nuc/HeNuc.png"), 2, 2],
'LiNuc': [185, 214, 40, 69, 1, 1.16 * 10 ** -26, pygame.image.load("nuc/LiNuc.png"), 8, 1],
'BeNuc': [216, 246, 40, 69, 2, 1.53 * 10 ** -26, pygame.image.load("nuc/BeNuc.png"), 8, 2],
'BNuc' : [428, 457, 40, 69, 3, 1.84 * 10 ** -26, pygame.image.load("nuc/BNuc.png"), 8, 3],
'CNuc' : [460, 489, 40, 69, 4, 2.04 * 10 ** -26, pygame.image.load("nuc/CNuc.png"), 8, 4],
'NNuc' : [492, 520, 40, 69, 5, 2.38 * 10 ** -26, pygame.image.load("nuc/NNuc.png"), 8, 5],
'ONuc' : [523, 551, 40, 69, 6, 2.72 * 10 ** -26, pygame.image.load("nuc/ONuc.png"), 8, 6],
'FNuc' : [554, 583, 40, 69, 7, 3.23 * 10 ** -26, pygame.image.load("nuc/FNuc.png"), 8, 7],
'NeNuc': [586, 613, 40, 69, 8, 3.43 * 10 ** -26, pygame.image.load("nuc/NeNuc.png"), 8, 8]}
menu = pygame.display.set_mode(sizeMenu)
screenColor = pygame.Color(255, 255, 220)
screen = pygame.display.set_mode(sizeScreen)
edgeObj = pygame.image.load("edge.png")
addEl = [pygame.image.load('addElectron1.png'), pygame.image.load('addElectron2.png')]
addAtom = [pygame.image.load("addAtom1.png"), pygame.image.load("addAtom2.png"), pygame.image.load("atomTable.png")]
addNucleus = [pygame.image.load("addNuc1.png"), pygame.image.load("addNuc2.png"), pygame.image.load("NucTable.png")]
while True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit(0)
elif event.type == MOUSEMOTION:
mx, my = event.pos
mouseState = pygame.mouse.get_pressed()
if mouseState[0]:
for key in press:
if press[key][0] < mx <press[key][1] and press[key][2] < my < press[key][3]:
pressed = key
press[key][4] = 1
if not mouseState[0] and pressed == 'Kel':
particles[len(particles)] = [mx, my, 0, 0, 'el', []]
pressed = ''
press['Kel'][4] = 0
if pressed != '':
if not mouseState[0]:
if press[pressed][0] < mx <press[pressed][1] and press[pressed][2] < my < press[pressed][3]:
press[pressed][4] = 2
pressed = ''
if press['Knuc'][4] == 2 or press['Katom'][4] == 2:
if mouseState[0]:
if 621 < mx < 651 and 2 < my < 14:
press['Knuc'][4] = 0
press['Katom'][4] = 0
if press['Knuc'][4] == 2:
for nuc in PTI:
if PTI[nuc][0] < mx < PTI[nuc][1] and PTI[nuc][2] < my < PTI[nuc][3]:
press['Knuc'][4] = 0
selected.append(nuc)
if press['Katom'][4] == 2:
for nuc in PTI:
if PTI[nuc][0] < mx < PTI[nuc][1] and PTI[nuc][2] < my < PTI[nuc][3]:
a = 0
selected.append(nuc)
while a < PTI[nuc][8]:
selected.append('el')
a += 1
press['Katom'][4] = 0
if selected != []:
if not mouseState[0]:
a = len(particles)
particles[a] = [mx, my, 0, 0, selected[0], [b for b in range(a+1, len(selected)-1)]]
for item in selected:
if item != selected[0]:
particles[len(particles)] = [mx, my, 0, 0, item, [a]]
selected = []
for each in particles:
check(each)
move(particles[each])
check(each)
if len(particles[each][5]) > 0 and particles[each][4] == 'el':
moveAtEls(each, particles[each][5][0])
particles[each][5] = []
screen.fill(screenColor)
for a in particles:
screen.blit(PTI[particles[a][4]][6], (particles[a][0] - 29, particles[a][1] - 31))
menu.blit(edgeObj, (0, 0))
menu.blit(addNucleus[press['Knuc'][4]], (2, 2))
menu.blit(addAtom[press['Katom'][4]], (2, 2))
menu.blit(addEl[press['Kel'][4]], (2, 2))
pygame.display.flip()
Sorry if I'm being a nuisance by posting all the code, but I'm a complete n00b
and I'm surprised I got this far without help. I know the whole thing is
untidy, but if you could help with the error I'd greatly appreciate it.
Next time I'll just stick to `print("Hello, World!")`
Answer: So, what I believe is happening is that when execute the line `angle =
findA(particles[el], particles[nuc]) + 0.001`, either the `el` variable or the
`nuc` variable is a list of some sort, rather then a single object.
This throws an error because `particles` is a dict, and you cannot have a list
or any mutable type as a key in a dict.
So, given that this error does not execute immediately, I suspect that
somewhere along the line, in a piece of code that is not immediately executed,
you are accidentally passing in a `list` of some sort.
* * *
If you did mean to look things up in the `particles` dict by using a list as a
key, then you should convert the list to a `tuple` first: tuples are like
lists, but are immutable, and so can be hashed and used as a key of a dict.
|
sl4a python make a Toast for android phone
Question: I wrote only this 3 lines in python using
[SL4A](http://code.google.com/p/android-scripting/):
import android
droid = android.Android()
droid.makeToast(u"ascc4r")
When this code runs, I get the following error:
pydev debugger: starting
Traceback (most recent call last):
File "C:\Users\Tibi\Desktop\adt-bundle-windows-x86_64-20130917\eclipse\plugins \org.python.pydev_2.8.2.2013090511\pysrc\pydevd.py", line 1446, in <module>
debugger.run(setup['file'], None, None)
File "C:\Users\Tibi\Desktop\adt-bundle-windows-x86_64-20130917\eclipse\plugins org.python.pydev_2.8.2.2013090511\pysrc\pydevd.py", line 1092, in run
pydev_imports.execfile(file, globals, locals) #execute the script
File "C:\Users\Tibi\workspace\26\src\26module.py", line 7, in <module>
droid = android.Android()
File "C:\Python26\lib\android.py", line 34, in __init__
self.conn = socket.create_connection(addr)
File "C:\Python26\lib\socket.py", line 547, in create_connection
for res in getaddrinfo(host, port, 0, SOCK_STREAM):
socket.gaierror: [Errno 11001] getaddrinfo failed
Environment setup: \- Python 2.6.6 \- set ap_port=9999 \- adb forward tcp:9999
tcp:xxxx (xxxx where I started the server on the phone) My android.py is in
the Python/Lib folder.
Update: I tried this 3 instruction in CMD and it's work, making a Toast. So I
think the fault is in the ADT bundle, or Eclipse Python plugin.
What is this Errno 11001?
Answer: > What is this Errno 11001?
I don't know about that error, but I suggest to use the correct syntax which
is
import android
droid = android.Android()
droid.makeToast('my text to print should be inside the quotes')
see also the [API Overview](http://code.google.com/p/android-
scripting/wiki/AndroidFacadeAPI)
|
Python 'shelve' that writes itself to disk after each operation
Question: I'm doing a project in Python that involves a lot of interactive work with a
persistent dictionary. If I weren't doing interactive development, I could use
contextlib.closing and be fairly confident that the shelf would get written to
disk eventually. But as it stands there's no chunk of code that I can easily
wrap within a 'with' statement. I'd prefer not to have to trust myself to call
close() on my shelf at the end of a session.
The amount of data involved is not large, and I would happily sync a shelf to
disk after each operation. I've found myself writing a wrapper for shelve that
does just that but I'm not a strong enough Python programmer to identify the
correct set of dict methods that I'd need to override. And it seems to me that
if what I'm doing is a good idea, it's probably been done before. What is the
paradigmatically correct way to handle this?
I'll add that I like using shelve because it's a simple module, and it comes
with Python. If possible I'd prefer to avoid doing something that requires
(for example) pulling in a complicated library for dealing with databases.
I'm using WinXP with SP3, Python 2.7.5 via Anaconda 1.6.2 (32-bit), and
running inside Spyder. I can tell by looking at the modified times for the
file backing my shelf that the shelf isn't updating until I call sync or
close.
Answer: What you can do is subclass `DbfilenameShelf` and override `__setitem__` and
`__delitem__` to automatically sync after each change. Something like this
would probably work (untested):
from shelve import DbfilenameShelf
class AutoSyncShelf(DbfilenameShelf):
# default to newer pickle protocol and writeback=True
def __init__(self, filename, protocol=2, writeback=True):
DbfilenameShelf.__init__(self, filename, protocol=protocol, writeback=writeback)
def __setitem__(self, key, value):
DbfilenameShelf.__setitem__(self, key, value)
self.sync()
def __delitem__(self, key):
DbfilenameShelf.__delitem__(self, key)
self.sync()
my_shelf = AutoSyncShelf("myshelf")
I can't vouch for the performance of this, of course.
|
Python coding - list index out of range
Question: lots of code up here
...
if c==excelfiles[1]:
b ==excelfiles[1]
wb = xlrd.open_workbook(a)
wb.sheet_names()
sh = wb.sheet_by_index(0)
for rownum in range(sh.nrows):
print sh.row_values(rownum)
for i in range(sheet.nrows):
cashflow = [sheet.cell_value(i,0)],[sheet.cell_value(i,1)],[sheet.cell_value(i,2)]
print cashflow
def npv(rate, cashflow):
value = cashflow[1] * ((1 + rate/100) ** (12 - cashflow[0]))
FV = 0
FV += value
return FV
def irr(cashflow, iterations = 100):
rate = 1.0
i = 0
while (cashflow[0][1] == 0):
i += 1
investment = cashflow[i][1]
for i in range(1, iterations+1):
rate *= (1 - (npv(rate, cashflow) / investment))
return rate
r = irr(cashflow)
print r
Error/Output:
File "<pyshell#90>", line 1, in <module>
import quarterZ
File "quarterZ.py", line 65, in <module>
r = irr(cashflow) # why is list index out of range?
File "quarterZ.py", line 56, in irr
while (cashflow[0][1] == 0):
IndexError: list index out of range
Can someone please explain why my list index is out of range? And can you show
me how to fix this? I am relatively new to python so I'm sure it's a stupid
mistake.
Thanks so much!
I've also attached the code here: <http://ideone.com/G5hGuK>
Answer: `cashflow[0]` is set to `[sheet.cell_value(i,0)]` in your for loop on line 10,
which is a list with length 1. The expression `cashflow[0][1]` is trying to
read the second value in that list.
|
More elegant/Pythonic way of printing elements of tuple?
Question: I have a function which returns a large set of integer values as a tuple. For
example:
def solution():
return 1, 2, 3, 4 #etc.
I want to elegantly print the solution without the tuple representation. (i.e.
parentheses around the numbers).
I tried the following two pieces of code.
print ' '.join(map(str, solution())) # prints 1 2 3 4
print ', '.join(map(str, solution())) # prints 1, 2, 3, 4
They both work but they look somewhat ugly and I'm wondering if there's a
better way of doing this. Is there a way to "unpack" tuple arguments and pass
them to the `print` statement in Python 2.7.5?
I would really love to do something like this:
print(*solution()) # this is not valid syntax in Python but I wish it was
kind of like tuple unpacking so that it's equivalent to:
print sol[0], sol[1], sol[2], sol[3] # etc.
Except without the ugly indexes. Is there any way to do that?
I know this is a stupid question because I'm just trying to get rid of
parentheses but I was just wondering if there was something I was missing.
Answer: `print(*solution())` actually _can be_ valid on python 2.7, just put:
from __future__ import print_function
On the top of your file.
You could also iterate through the tuple:
for i in solution():
print i,
This is equivalent to:
for i in solution():
print(i, end= ' ')
If you ever use Python 3 or the import statement above.
|
Python: Print using ascii codes
Question: I'm a beginner in python and I'm having a problem in this program:
Here's the NodeList first:
class Node:
def __init__(self,initdata):
self.data = initdata
self.next = None
def getData(self):
return self.data
def getNext(self):
return self.next
def setData(self,newdata):
self.data = newdata
def setNext(self,newnext):
self.next = newnext
My problem is in this program: (The print)
from NodeList import Node
class StackLL:
def __init__(self):
self.head = None
def pushSLL(self,item):
temp = Node(str(item))
temp.setNext(self.head)
self.head = temp
node = self.head
print(chr(0x2510)+(chr(0x0000)*(len(item)))+chr(0x250c))
while node!=None:
stackeditem = chr(0x2502)+node.data+chr(0x2502)
print(stackeditem)
node = node.next
print(chr(0x2514)+(chr(0x2500)*(len(item)-1))+chr(0x2518))
Everytime I print, the lines just seems off. I tried to experiment using len()
just to make it accurate, but everytime the item adds more characters it gets
off again. Any help would be greatly appreciated. Thank you.
Answer: Use a monospace font in IDLE settings and you are all good.
|
Getting different result in different runs with multithreading
Question: why when the code executed, the result different every time?
i tried to follow how the code is executed, and i confused, i feel this is not
sense.
and the result appear randomly every time
#!/usr/bin/python
import Queue
import threading
import time
exitFlag = 0
class myThread (threading.Thread):
def __init__(self, threadID, name, q):
threading.Thread.__init__(self)
self.threadID = threadID
self.name = name
self.q = q
def run(self):
print "Starting " + self.name
process_data(self.name, self.q)
print "Exiting " + self.name
def process_data(threadName, q):
while not exitFlag:
queueLock.acquire()
if not workQueue.empty():
data = q.get()
queueLock.release()
print "%s processing %s" % (threadName, data)
else:
queueLock.release()
time.sleep(1)
threadList = ["Thread-1", "Thread-2", "Thread-3"]
nameList = ["One", "Two", "Three", "Four", "Five"]
queueLock = threading.Lock()
workQueue = Queue.Queue(10)
threads = []
threadID = 1
# Create new threads
for tName in threadList:
thread = myThread(threadID, tName, workQueue)
thread.start()
threads.append(thread)
threadID += 1
# Fill the queue
queueLock.acquire()
for word in nameList:
workQueue.put(word)
queueLock.release()
# Wait for queue to empty
while not workQueue.empty():
pass
# Notify threads it's time to exit
exitFlag = 1
# Wait for all threads to complete
for t in threads:
t.join()
print "Exiting Main Thread"
code source <http://www.tutorialspoint.com/python/python_multithreading.htm>
* * *
**update**
Sorry, i mean the order of result
like this:
Starting Thread-1
Starting Thread-2
Starting Thread-3
Thread-3 processing One
Thread-2 processing Two
Thread-1 processing Three
Thread-3 processing Four
Thread-2 processing Five
Exiting Thread-1
Exiting Thread-3
Exiting Thread-2
Exiting Main Thread
[Finished in 3.0s]
and when try again, the result
Starting Thread-1
Starting Thread-2
Starting Thread-3
Thread-3 processing One
Thread-2 processing Two
Thread-1 processing Three
Thread-3 processing Four
Thread-3 processing Five
Exiting Thread-1
Exiting Thread-2
Exiting Thread-3
Exiting Main Thread
[Finished in 3.0s]
Answer: I assume, by "result" you mean the execution order. One idea behind
mutithreading is, that you don't have to care about execution order unless you
want to specify it explicitely. You are totally dependent on the underlying
operating system, system load, ... etc.
|
Python, OpenCV: classify gender using ORB features and KNN
Question: **Task:** Classify images of human faces as female or male. Training images
with labels are available, obtain the test image from webcam.
**Using:** Python 2.7, OpenCV 2.4.4
I am using ORB to extract features from a grayscale image which I hope to use
for training a K-Nearest Neighbor classifier. Each training image is of a
different person so the number of keypoints and descriptors for each image are
obviously different. My problem is that I'm not able to understand the OpenCV
docs for KNN and ORB. I've seen other SO questions about ORB, KNN and FLANN
but they didn't help much.
What exactly is the nature of the descriptor given by ORB? How is it different
than descriptors obtained by BRIEF, SURF, SIFT, etc.?
It seems that the feature descriptors should be of the same size for each
training sample in KNN. How do I make sure that the descriptors are of the
same size for each image? More generally, in what format should features be
presented to KNN for training with given data and labels? Should the data be
an int or float? Can it be char?
The training data can be found
[here](https://drive.google.com/folderview?id=0B2AJ7rliSQubRmRXd2dJa0pXTnc&usp=sharing).
I am also using the `haarcascade_frontalface_alt.xml` from opencv samples
Right now the KNN model is given just 10 images for training to see if my
program passes without errors which, it does not.
Here is my code:
import cv2
from numpy import float32 as np.float32
def chooseCascade():
# TODO: Option for diferent cascades
# HAAR Classifier for frontal face
_cascade = cv2.CascadeClassifier('haarcascade_frontalface_alt.xml')
return _cascade
def cropToObj(cascade,imageFile):
# Load as 1-channel grayscale image
image = cv2.imread(imageFile,0)
# Crop to the object of interest in the image
objRegion = cascade.detectMultiScale(image) # TODO: What if multiple ojbects in image?
x1 = objRegion[0,0]
y1 = objRegion[0,1]
x1PlusWidth = objRegion[0,0]+objRegion[0,2]
y1PlusHeight = objRegion[0,1]+objRegion[0,3]
_objImage = image[y1:y1PlusHeight,x1:x1PlusWidth]
return _objImage
def recognizer(fileNames):
# ORB contructor
orb = cv2.ORB(nfeatures=100)
keyPoints = []
descriptors = []
# A cascade for face detection
haarFaceCascade = chooseCascade()
# Start processing images
for imageFile in fileNames:
# Find faces using the HAAR cascade
faceImage = cropToObj(haarFaceCascade,imageFile)
# Extract keypoints and description
faceKeyPoints, faceDescriptors = orb.detectAndCompute(faceImage, mask = None)
#print faceDescriptors.shape
descRow = faceDescriptors.shape[0]
descCol = faceDescriptors.shape[1]
flatFaceDescriptors = faceDescriptors.reshape(descRow*descCol).astype(np.float32)
keyPoints.append(faceKeyPoints)
descriptors.append(flatFaceDescriptors)
print descriptors
# KNN model and training on descriptors
responses = []
for name in fileNames:
if name.startswith('BF'):
responses.append(0) # Female
else:
responses.append(1) # Male
knn = cv2.KNearest()
knnTrainSuccess = knn.train(descriptors,
responses,
isRegression = False) # isRegression = false, implies classification
# Obtain test face image from cam
capture = cv2.VideoCapture(0)
closeCamera = -1
while(closeCamera < 0):
_retval, _camImage = capture.retrieve()
# Find face in camera image
testFaceImage = haarFaceCascade.detectMultiScale(_camImage) # TODO: What if multiple faces?
# Keyponts and descriptors of test face image
testFaceKP, testFaceDesc = orb.detectAndCompute(testFaceImage, mask = None)
testDescRow = testFaceDesc.shape[0]
flatTestFaceDesc = testFaceDesc.reshape(1,testDescRow*testDescCol).astype(np.float32)
# Args in knn.find_nearest: testData, neighborhood
returnedValue, result, neighborResponse, distance = knn.find_nearest(flatTestFaceDesc,3)
print returnedValue, result, neighborResponse, distance
# Display results
# TODO: Overlay classification text
cv2.imshow("testImage", _camImage)
closeCamera = cv2.waitKey(1)
cv2.destroyAllWindows()
if __name__ == '__main__':
fileNames = ['BF09NES_gray.jpg',
'BF11NES_gray.jpg',
'BF13NES_gray.jpg',
'BF14NES_gray.jpg',
'BF18NES_gray.jpg',
'BM25NES_gray.jpg',
'BM26NES_gray.jpg',
'BM29NES_gray.jpg',
'BM31NES_gray.jpg',
'BM34NES_gray.jpg']
recognizer(fileNames)
Currently I am getting an error at the line with `knn.train()` where
`descriptors` is not detected as a numpy array.
Also, is this approach completely wrong? Am I supposed to use some other way
for gender classification? I wasn't satisfied with the fisherface and
eigenface example in the opencv facerec demo so please don't direct me to
those.
Any other help is much appreciated. Thanks.
**\--- EDIT ---**
I've tried a few things and come up with an answer.
I am still hoping that someone in SO community can help me by suggesting an
idea so that I don't have to hardcode things into my solution. I also suspect
that knn.match_nearest() isn't doing what I need it to do.
And as expected, the recognizer is not at all accurate and very prone to
giving misclassification due to rotation, lighting, etc. Any suggestions on
improving this approach would be really appreciated.
The database I am using for training is: [Karolinska Directed Emotional
Faces](http://www.emotionlab.se/resources/kdef)
Answer: i have some doubts on the effectiveness/workability of the described approach.
here's a another approach that you might want to consider. the contents of
`gen` folder is @ <http://www1.datafilehost.com/d/0f263abc>. as you will note
when the data size gets bigger(~10k training samples), the size of the model
may become unacceptable(~100-200mb). then you will need to look into pca/lda
etc.
import cv2
import numpy as np
import os
def feaCnt():
mat = np.zeros((400,400,3),dtype=np.uint8)
ret = extr(mat)
return len(ret)
def extr(img):
return sobel(img)
def sobel(img):
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
klr = [[-1,0,1],[-2,0,2],[-1,0,1]]
kbt = [[1,2,1],[0,0,0],[-1,-2,-1]]
ktb = [[-1,-2,-1],[0,0,0],[1,2,1]]
krl = [[1,0,-1],[2,0,-2],[1,0,-1]]
kd1 = [[0,1,2],[-1,0,1],[-2,-1,0]]
kd2 = [[-2,-1,0],[-1,0,1],[0,1,2]]
kd3 = [[0,-1,-2],[1,0,-1],[2,1,0]]
kd4 = [[2,1,0],[1,0,-1],[0,-1,-2]]
karr = np.asanyarray([
klr,
kbt,
ktb,
krl,
kd1,
kd2,
kd3,
kd4
])
gray=cv2.resize(gray,(40,40))
res = np.float32([cv2.resize(cv2.filter2D(gray, -1,k),(15,15)) for k in karr])
return res.flatten()
root = 'C:/data/gen'
model='c:/data/models/svm/gen.xml'
imgs = []
idx =0
for path, subdirs, files in os.walk(root):
for name in files:
p =path[len(root):].split('\\')
p.remove('')
lbl = p[0]
fpath = os.path.join(path, name)
imgs.append((fpath,int(lbl)))
idx+=1
samples = np.zeros((len(imgs),feaCnt()),dtype = np.float32)
labels = np.zeros(len(imgs),dtype = np.float32)
i=0.
for f,l in imgs:
print i
img = cv2.imread(f)
samples[i]=extr(img)
labels[i]=l
i+=1
svm = cv2.SVM()
svmparams = dict( kernel_type = cv2.SVM_POLY,
svm_type = cv2.SVM_C_SVC,
degree=3.43,
gamma=1.5e-4,
coef0=1e-1,
)
print 'svm train'
svm.train(samples,labels,params=svmparams)
svm.save(model)
print 'done'
result = np.float32( [(svm.predict(s)) for s in samples])
correct=0.
total=0.
for i,j in zip(result,labels):
total+=1
if i==j:
correct+=1
print '%f'%(correct/total)
|
Python logging root handler does not capture all
Question: I've got an issue with a root logger which I expected to work as a catch-all
logger for anything that doesn't match other places. It's not working as I
expected however. Here's a simplified logging configuration I use:
[loggers]
keys = root, specific
[handlers]
keys = syslog
[formatters]
keys = default
[logger_root]
level = WARNING
handlers = syslog
[logger_specific]
level = DEBUG
handlers = syslog
qualname = specific
[handler_syslog]
class = handlers.SysLogHandler
args = (('localhost',514), handlers.SysLogHandler.LOG_LOCAL0)
formatter = default
[formatter_default]
format = %(message)s
Now when I log anything from a module called `specific.something.else`, it
gets logged properly. If I log from a `different.module`, I don't get that
line at all. I can add more of the "specific" loggers and they capture the
additional messages just fine... but how can I make the root logger a "catch-
all" one? I was under the impression that it should do that role by default.
Answer: It's probably because your `different.module` loggers were created _before_
the `fileConfig` call, which results in those loggers being disabled in the
call.
You need to ensure that you call `fileConfig` with
`disable_existing_loggers=False`, and be running Python 2.6 or later so that
you can use this keyword argument. If you can't do this, you'll need to avoid
creating any loggers (other than those which are named, or whose ancestors are
named, in the configuration) until _after_ `fileConfig` has been called.
See also [this
answer](http://stackoverflow.com/questions/9608717/incompatibility-between-
import-time-logger-naming-with-logging-configuration).
|
Python BeautifulSoup Ampersand issue Mac vs. Linux Ubuntu
Question: I've read that BeautifulSoup has problems with ampersands (&) which are not
strictly correct in HTML but still interpreted correctly by most browsers.
However weirdly I'm getting different behaviour on a Mac system and on a
Ubuntu system, both using bs4 version 4.3.2:
html='<td>S&P500</td>'
s=bs4.BeautifulSoup(html)
On the Ubuntu system s is equal to:
<td>S&P500;</td>
Notice the added semicolon at the end which is a real problem
On the mac system:
<html><head></head><body>S&P500</body></html>
Never mind the html/head/body tags, I can deal with that, but notice S&P 500
is correctly interpreted this time, without the added ";".
Any idea what's going on? How to make cross-platform code without resorting to
an ugly hack? Thanks a lot,
Answer: First I can't reproduce the mac results using python2.7.1 and
beautifulsoup4.3.2, that is I am getting the extra semicolon on all systems.
The easy fix is a) use strictly valid HTML, or b) add a space after the
ampersand. Chances are you can't change the source, and if you could parse out
and replace these in python you wouldn't be needing BeautifulSoup ;)
So the problem is that the BeautifulSoupHTMLParser first converts `S&P500` to
`S&P500;` because it assumes `P500` is the character name and you just forgot
the semicolon.
Then later it reparses the string and finds `&P500;`. Now it doesn't recognize
`P500` as a valid name and converts the `&` to `&` without touching the
rest.
Here is a stupid monkeypatch **only to demonstrate my point**. I don't know
the inner workings of BeautifulSoup well enough to propose a proper solution.
from bs4 import BeautifulSoup
from bs4.builder._htmlparser import BeautifulSoupHTMLParser
from bsp.dammit import EntitySubstitution
def handle_entityref(self, name):
character = EntitySubstitution.HTML_ENTITY_TO_CHARACTER.get(name)
if character is not None:
data = character
else:
# Previously was
# data = "&%s;" % name
data = "&%s" % name
self.handle_data(data)
html = '<td>S&P500</td>'
# Pre monkeypatching
# <td>S&P500;</td>
print(BeautifulSoup(html))
BeautifulSoupHTMLParser.handle_entityref = handle_entityref
# Post monkeypatching
# <td>S&P500</td>
print(BeautifulSoup(html))
Hopefully someone more versed in bs4 can give you a proper solution, good
luck.
|
Downloading PDF's with Webdriver
Question: I am trying to download pdfs with selenium webdriver with python bindings on
OS X 10.8.
I actually need the pdf file, not just check if it the download link works. As
I understand it, I need to set the firefox profile to download the pdf content
type, rather than 'preview' which is the default.
My code to open an instance of firefox is:
def Engage():
print "Start Up FIREFOX"
## Create a new instance of the Firefox driver
profile = webdriver.firefox.firefox_profile.FirefoxProfile()
profile.set_preference('browser.download.folderList', 2)
profile.set_preference('browser.download.dir', os.path.expanduser("~/Documents/PYTHON/Download_Files/tmp/"))
profile.set_preference('browser.helperApps.neverAsk.saveToDisk', ('application/pdf'))
driver = webdriver.Firefox(firefox_profile=profile)
return driver
I have also tried initially setting the profile as :
profile = webdriver.FirefoxProfile()
## replacing :: profile = webdriver.firefox.firefox_profile.FirefoxProfile()
## the other attributes remained
This has the same results
This profile opens the pdf in preview mode in a new window, rather than
download it.
I double checked the content type through requests and was able to confirm it
as "application/pdf":
import requests
print requests.head('mywebsite.com').headers['content-type']
Any idea of what I am doing wrong?
Answer: Was facing a similar situation sometime back. Solution is quite easy. By
default the settings in firefox opens pdf files rather than allowing you to
download it. To overcome this type config:about in the browser and type
pdfjs.disabled double click on the option. The value should change from false
to true. Restart the browser and try opening any pdf file. It will download
the file instead of opening it in the browser. Happy coding.
|
Seeming discrepancy in shutil.disk_usage()
Question: Hello StackOverflow folks, Longtime reader, first time poster. Hopefully I've
got all the info here to make a useful question.
I am using the shutil.disk_usage() function to find the current disk usage of
a particular path (amount available, used, etc.). As far as I can find, this
is a wrapper around os.statvfs() calls. I'm finding that it is not giving the
answers I'd expect, as comparing to the output of "du" in Linux.
I have obscured some of the paths below for company privacy reasons, but the
output and code are otherwise undoctored. I am using Python 3.3.2 64-bit
version.
#!/apps/python/3.3.2_64bit/bin/python3
# test of shutils.diskusage module
import shutil
BytesPerGB = 1024 * 1024 * 1024
(total, used, free) = shutil.disk_usage("/data/foo/")
print ("Total: %.2fGB" % (float(total)/BytesPerGB))
print ("Used: %.2fGB" % (float(used)/BytesPerGB))
(total1, used1, free1) = shutil.disk_usage("/data/foo/utils/")
print ("Total: %.2fGB" % (float(total1)/BytesPerGB))
print ("Used: %.2fGB" % (float(used1)/BytesPerGB))
Which outputs:
/data/foo/drivecode/me % disk_usage_test.py
Total: 609.60GB
Used: 291.58GB
Total: 609.60GB
Used: 291.58GB
As you can see, the main problem is I would expect the second amount for
"Used" to be much smaller, as it is a subset of the first directory.
/data/foo/drivecode/me % du -sh /data/foo/utils
2.0G /data/foo/utils
As much as I trust "du," I find it hard to believe the Python module would be
incorrect either. So perhaps it is just my understanding of Linux filesystems
that could be the issue. :)
I wrote a module (based heavily on someone's code here at SO) which
recursively gets the disk_usage, which I was using until now. It appears to
match the "du" output but is MUCH, much slower than the shutil.disk_usage()
function, so I'm hoping I can make that one work.
Thanks much in advance.
Answer: The problem is that shutil uses the [`statvfs`](http://man7.org/linux/man-
pages/man2/statvfs.2.html) system call underneath to determine the space used.
This system call has no file-path granularity as far as I'm aware, only file-
system granularity. What this means is that the path you provide it with only
helps to identify the file system you want to query, not the path's.
In other words, you gave it the path `/data/foo/utils` and then it determined
which file system backs this file path. Then it queried _the file system_.
This becomes apparent when you consider how the `used` parameter is defined in
shutil:
used = (st.f_blocks - st.f_bfree) * st.f_frsize
Where:
fsblkcnt_t f_blocks; /* size of fs in f_frsize units */
fsblkcnt_t f_bfree; /* # free blocks */
unsigned long f_frsize; /* fragment size */
This is why it's giving you the _total_ space used on the entire file system.
Indeed, it seems to me like the `du` command itself also traverses the file
structure and adds up the file sizes. Here is GNU coreutils `du` command's
[source code](https://github.com/goj/coreutils/blob/rm-d/src/du.c).
|
python + opencv "dll load failed"
Question: I'm trying to install opencv on my machine as explained in the book: "Packtpub
OpenCV Computer Vision with Python Apr 2013"
It says that in order to run kinect you need to compile openCV with some stuff
in it, so I downloaded openCV .exe that extracts to a 3.2gb folder and
proceeded with all the steps...
Used CMaker, used the compiler MinGW, and everything as the book said
Than it tells me to try running some examples... but when I try to run
drawing.py as recommended by the book, and all the others, it says:
python drawing.py
* * *
OpenCV Python version of drawing
traceback< most recent call last>:
File "drawing.py", line 7, in
import cv2.cv as cv
ImportError: DLL load failed: Invalid access to memory location.
* * *
I saw a lot of people saying this problem is fixed by adding the path to the
bin of openCV dlls to path...
how do I find out which dll name is missing so I can find the name of it and
find the folder where it is?
I have a x64 computer but the book tells me to install everything x86 because
it is harder to get some minor bugs, maybe a version incompatibility between
openCV, compiler, cmaker, and python?
I've tried to add a lot of folders to "path" variable and it didn't work
please tell me how I find out which dlls are missing so I can search for them
on the computer or some other way to solve this problem because I'm just out
of ideas
Answer: I don't have a high enough rep to add a comment otherwise I would but
something you can do is start python with the -v option.
doing that will add a bit more to the output console and it will cause the
python VM to output where it is looking for things when it tries looking for
things, especially when failures occur. I've found that to be helpful when
trying to hunt problems such as path problems down.
It also sounds like you haven't got your paths setup correctly. Have you
looked at [ImportError: DLL load failed: %1 is not a valid Win32
application](http://stackoverflow.com/questions/14629818/importerror-dll-load-
failed-1-is-not-a-valid-win32-application?rq=1) ? If a DLL was expected in a
certain location but wasn't loaded or present but then 'called' via a
LoadLibrary (without checking to see if it was actually loaded) that might
cause such an error. It is probably the fault of the original DLL that failed
to verify the subsequent DLL was loaded instead of just assuming the
LoadLibrary call succeeded.
In addition to the python -v yourmodule.py option you could also try running
an strace (if you are on unix -- but it doesn't sound like you are). I used to
use SoftICE on Windows for digging down deep. If you know the package or the
DLL that is at the root of the problem, and have access to a dll export tool,
you should be able to get a list of the dependencies the dll needs (external
functions it relies on). Then you just need to know or find those functions it
relies on from other DLLs. It's been awhile since I used to had do this sort
of stuff all the time to locate functions in other DLLs but it is something
that is entirely doable from a spelunkers perspective. But there are probably
easier ways to go about it.
I'd start with the python -v approach first.
|
Generating a random email using python 3.2
Question: I would like to generate a 64 letter for a random email. There are a few
restriction so as to follow the email syntax. But I am not sure why doesnt my
output display anything. Is there something wrong with my if statement?
import random
y=" "
for x in range (0,64):
z = random.randint(33,127)
if z in [32,34,40,41,44,58,59,60,62,64,91,92,93] == False:
b = chr(z)
print(b)
Answer: This:
if z in [32,34,40,41,44,58,59,60,62,64,91,92,93] == False:
is equivalent to:
if z in [32,34,40,41,44,58,59,60,62,64,91,92,93] and [32,34,40,41,44,58,59,60,62,64,91,92,93] == False:
which never evaluates to True, you probably meant to do:
if z not in [32,34,40,41,44,58,59,60,62,64,91,92,93]:
|
Conflicting versions of python in ubuntu
Question: So i had python 2.7.2 on my server and i needed to update it to python 2.7.3.
So i've tried to remove the 2.7.2 version and then install the new one using
the sources. I wasn't able to remove the 2.7.2 version cause the system uses
it to run crucial services on server, so i installed the 2.7.3 version in hope
that after that i would be able to remove the old version. Still i cant remove
the old version, although i'm able to execute the python 2.7.3 when i install
any module i cant import it. I added the path to sys.path and i started
finding the module but importing it causes another errors.
My python executes the /usr/local/bin/python which is the 2.7.3 version where
the problems are. If i try to execute python like this /usr/bin/python it
executes the old version and everything works fine there, i can import the new
installed modules.
So what can i do to make python 2.7.3 work?
I've searched a lot of tutorials and tried things like add the library in .pth
files on python and i started finding the modules but when importing it i get
errors like this:
>>> import numpy
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/numpy/__init__.py", line 137, in <module>
import add_newdocs
File "/usr/local/lib/python2.7/dist-packages/numpy/add_newdocs.py", line 9, in <module>
from numpy.lib import add_newdoc
File "/usr/local/lib/python2.7/dist-packages/numpy/lib/__init__.py", line 4, in <module>
from type_check import *
File "/usr/local/lib/python2.7/dist-packages/numpy/lib/type_check.py", line 8, in <module>
import numpy.core.numeric as _nx
File "/usr/local/lib/python2.7/dist-packages/numpy/core/__init__.py", line 5, in <module>
import multiarray
ImportError: /usr/local/lib/python2.7/dist-packages/numpy/core/multiarray.so: undefined symbol: PyUnicodeUCS4_AsUnicodeEscapeString
Thanks for the help
EDIT PROBLEM SOLvED
So to solve the missing import modules i created a .pth file under
/usr/local/lib/python2.7/site-packages/ with the directories where the python
modules are and the python starts to find them. To fix the comptability
problems you can install python from sources and specify the unicode doing
./configure --enable-unicode
more information
[here](http://bytes.com/topic/python/answers/163553-undefined-symbol-
pyunicodeucs4)
Answer: Do not EVER mess with system python, EVER.
What you should do is install python 2.7.3 with a --prefix into your home
directory, then use `virtualenv -p /home/myuser/path/to/python`.
In any case, using virtualenv to run your own application is almost always a
good idea, as it avoids polluting the system package directories with
libraries you use in your own applications.
|
Python lxml and parsing a subtree
Question: I've got a xml which looks like this:
<root>
<foo>
<a></a>
<b></b>
<c></c>
</foo>
<bars>
<bar>
<one>interesting</one>
<two>interesting</two>
<three>interesting</three>
</bar>
<bar>
<one>interesting</one>
<two>interesting</two>
<three>interesting</three>
</bar>
<bar>
<one>interesting</one>
<two>interesting</two>
<three>interesting</three>
</bar>
</bars>
<root>
I want to extract the interesting text from all the bars. Can you tell me how
to start? I've tried to use
bars = etree.iterparse(xml_data, tag="bars")
but I couldn't iterate through it.
Answer: Use `findall` method to return all matching elements.
xml_data = '''<?xml version='1.0' encoding='ASCII' ?>
<root>
<foo>
<a></a>
<b></b>
<c></c>
</foo>
<bars>
<bar>
<one>interesting</one>
<two>interesting</two>
<three>interesting</three>
</bar>
<bar>
<one>interesting</one>
<two>interesting</two>
<three>interesting</three>
</bar>
<bar>
<one>interesting</one>
<two>interesting</two>
<three>interesting</three>
</bar>
</bars>
</root>
'''
from lxml import etree
root = etree.fromstring(xml_data)
for bars in root.findall('.//bars'):
print(etree.tostring(bars, method='text'))
|
TCL in Python: can't find package
Question: I am trying to run a TCL script from python. There is a very specific TCL
package embedded in some software I am using and I need to tell the python
interpreter (or TKinter ?) where this package is. Here is what I have tried so
far.
>>> import Tkinter
>>> r = Tkinter.Tk()
>>> r.tk.eval('lappend auto_path C:/Program Files (x86)/Ixia/IxNetwork/7.0-EA/tcl8.4/bin')
>>> r.tk.eval('lappend auto_path C:\\Program Files (x86)\\Ixia\\IxNetwork\7.0-EA\\tcl8.4\\bin\\')
'{C:\\Python26\\tcl\\tcl8.5} C:/Python26/tcl C:/lib {C:\\Python26\\tcl\\tk8.5} {C:\\Python26\\tcl\\tk8.5/ttk} C:/Program Files (x86)/Ixia/IxNetwork/7.0-EA/tcl8.4/bin C:Program Files (x86)IxiaIxNetwork\x07.0-EA\\tcl8.4\x08in\\\\'
I want to use the following TCL shell which I copied from the windows start
menu:
"C:\Program Files (x86)\Ixia\IxOS\6.40-EA\TclScripts\bin\wish84.exe" "C:\Program Files (x86)\Ixia\IxOS\6.40-EA\TclScripts\bin\IxiaWish.tcl"
Firstly, can someone tell me why there are two items being referred to in the
start menu shortcut target? Will I be able to access this for my TCL in
python?
As you can see from above, I have tried appending this package to the
auto_path, but there are problems with characters. Does anyone know why the
characters are mixed up?
Answer: I don't understand what you are trying to accomplish. If all you want to do is
to execute the following command:
"C:\Program Files (x86)\Ixia\IxOS\6.40-EA\TclScripts\bin\wish84.exe" "C:\Program Files (x86)\Ixia\IxOS\6.40-EA\TclScripts\bin\IxiaWish.tcl"
Then why not use `subprocess`? Something along this line:
import subprocess
command = [
r'C:\Program Files (x86)\Ixia\IxOS\6.40-EA\TclScripts\bin\wish84.exe',
r'C:\Program Files (x86)\Ixia\IxOS\6.40-EA\TclScripts\bin\IxiaWish.tcl'
]
p = subprocess.Popen(commands,
shell=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
|
How to convert occurence matrix to co-occurence matrix in Python
Question: I asked this question here: [How to convert occurence matrix to co-occurence
matrix](http://stackoverflow.com/questions/19253300/how-to-convert-occurence-
matrix-to-co-occurence-matrix)
I realized that my data is so big that it is not possible to do this using R.
My computer hangs. The actual data is a text file with ~5 million rows and 600
columns. I think Python may be an alternate option to do this.
Answer: This would be the way you translate the `R` code to `Python` code.
>>> import numpy as np
>>> a=np.array([[0, 1, 0, 0, 1, 1],
[0, 0, 1, 1, 0, 1],
[1, 1, 1, 1, 0, 0],
[1, 1, 1, 0, 1, 1]])
>>> acov=np.dot(a.T, a)
>>> acov[np.diag_indices_from(acov)]=0
>>> acov
array([[0, 2, 2, 1, 1, 1],
[2, 0, 2, 1, 2, 2],
[2, 2, 0, 2, 1, 2],
[1, 1, 2, 0, 0, 1],
[1, 2, 1, 0, 0, 2],
[1, 2, 2, 1, 2, 0]])
However, you have a very big dataset. If you don't want to assemble the co-
occurence matrix piece by piece and you store your values in `int64`, with
3e+9 numbers it will take 24GB of RAM alone just to hold the data
<http://www.wolframalpha.com/input/?i=3e9+>*+8+bytes. So you probably want to
think over and decide which `dtype` you want to store your data in:
<http://docs.scipy.org/doc/numpy/user/basics.types.html>. Using `int16`
probably will make the `dot` product operation possible on a decent desktop PC
nowadays.
|
tab delimited to csv
Question: I am able to get this to output my MYSQL command which I have removed for
security, however I keep getting an error when I try and write this tab
delimited output to a CSV. Any help to boost the Python rookie would be
appreciated.
#!/usr/bin/pytho
import sys, csv
import MySQLdb
import os
import mysql.connector
import subprocess
import string
if __name__ == '__main__':
du = sys.argv[1]
csv_home = '/home/oatey/bundle_' + du + '.csv'
input = sys.stdin
output = sys.stdout
#read and rewrite to file with arguement
new = open("/home/oatey/valid.sql2", "w")
with open("/home/oatey/bundle.sql")as write_query:
#read_file = write_query.read()
for line in write_query:
lr = line.replace('{$$}', du)
print lr
new.write(lr)
new.close()
write_query.close()
with open("/home/oatey/valid.sql2") as w:
mysql_output = subprocess.check_output(MYSQL_COMMAND, stdin=w)
#print mysql_output
b = open("/home/oatey/" + du + ".txt", "r+")
#",".join("%s" % i for i in mysql_output
b.write(mysql_output)
print mysql_output
b.close()
#read tab-delimited file
with open("/home/oatey/" + du + ".txt", 'rb') as data:
cr = data.readlines()
contents = [line for line in cr]
with open("/home/oatey/" + du + ".csv", "wb") as wd:
cw = csv.writer(wd, quotechar='', quoting=csv.QUOTE_NONE)
wd.write(contents)
Answer: I bet the error you are getting is:
> TypeError: must be string or buffer, not list
`contents` is a list, you cannot write a list via `write()`. Quote from
[docs](http://docs.python.org/2/library/stdtypes.html#file.write):
> file.write(str)
>
> Write a string to the file.
Instead, use
[csvwriter.writerows()](http://docs.python.org/2/library/csv.html#csv.csvwriter.writerows):
with open("/home/oatey/" + du + ".csv", "wb") as wd:
cw = csv.writer(wd, quotechar='', quoting=csv.QUOTE_NONE)
cw.writerows(contents)
|
Unintented multithreading in python (scikit-learn)
Question: I'm using mixture submodule of sklearn module for Gaussian Mixture Model...
When I run my code on a multicore system, it uses multiple cores even though I
do not ask for it in the code. Is this a default behavior? And more important,
how can I disable it?
Thanks
Answer: thanks @prgao
the answer is there [Python: How do you stop numpy from
multithreading?](http://stackoverflow.com/questions/17053671/python-how-do-
you-stop-numpy-from-multithreading)
setting "export MKL_NUM_THREADS=1" seems to be working
|
How i should store simple objects using python and redis?
Question: Lets suppose that I have a lot of(hundreds) _big_ python dictionaries. Pickled
file size is about 2Mb. I want to draw chart using data from this dictionaries
so i have to load them all. What is the most efficent (at first speed, at
second memory) way to store my data? May be I should use another caching tool?
This how i am solving this task now:
1. Pickle every my dictionary. Just pickle(dict)
2. Load the pickled string to redis. redis.set(key, dict)
3. When user needs chart, i am creating array and fill it with unpickled data from redis. Just like that:
array = []
for i in range(iteration_count):
array.append(unpickle(redis.get(key)))
Now i have both problems: with memory, cause my array is very big, but its not
important and easy to solve. The main problem - speed. A lot of objects
unpickling more than 0.3 seconds. I even have bottlenecks with more than 1
second unpickling time. And getting this string from redis rather expensive
(more than 0.01 sec). When i have lots of objects, my user have to wait a lot
of seconds.
Answer: If it can be assumed that you are asking in the context of a web application
and that you are displaying your charts in a browser, I would definitely
recommend storing your dictionaries as JSON in redis.
Again, you have not provided too many details about your application, but I
have implemented charting over very large data sets before (100,000's of
sensor data points per second over several minutes of time). To help
performance when rendering the datasets, I stored each type of data into their
own dictionary or 'series'. This strategy allows you to render only portions
of the data as required.
Perhaps if you share more about your particular application we may be able to
provide more help.
|
How to solve UnicodeDecodeError in mezzanine?
Question: I am using mezzanine cms. When I scrap the data from the blogspot I got this
error
blog_id: sanavitastudio
Traceback (most recent call last):
File "/home/nyros/hs/git_br/2013/Oct-9/healersource/apps/blog_hs/forms.py", line 226, in save
blog_id=blog_id)
File "/home/nyros/hs/1a9pinaxenv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 150, in call_command
return klass.execute(*args, **defaults)
File "/home/nyros/hs/1a9pinaxenv/local/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute
output = self.handle(*args, **options)
File "/home/nyros/hs/git_br/mezzanine/mezzanine/blog/management/base.py", line 172, in handle
post, created = BlogPost.objects.get_or_create(**initial)
File "/home/nyros/hs/1a9pinaxenv/local/lib/python2.7/site-packages/django/db/models/manager.py", line 134, in get_or_create
return self.get_query_set().get_or_create(**kwargs)
File "/home/nyros/hs/1a9pinaxenv/local/lib/python2.7/site-packages/django/db/models/query.py", line 452, in get_or_create
obj.save(force_insert=True, using=self.db)
File "/home/nyros/hs/git_br/mezzanine/mezzanine/core/models.py", line 221, in save
super(Displayable, self).save(*args, **kwargs)
File "/home/nyros/hs/git_br/mezzanine/mezzanine/core/models.py", line 77, in save
super(Slugged, self).save(*args, **kwargs)
File "/home/nyros/hs/git_br/mezzanine/mezzanine/core/models.py", line 46, in save
super(SiteRelated, self).save(*args, **kwargs)
File "/home/nyros/hs/git_br/mezzanine/mezzanine/core/models.py", line 116, in save
self.description = strip_tags(self.description_from_content())
File "/home/nyros/hs/git_br/mezzanine/mezzanine/core/models.py", line 146, in description_from_content
description = unicode(self)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 5: ordinal not in range(128)
Code:
import xmltest
blog_id = xmltest.blogname(self.cleaned_data['blog_id'])
print(type(blog_id))
call_command(
'import_blogger_hs',
mezzanine_user=request.user.username,
blog_id=blog_id)
return False
And blogname method for If you give blogname it will automatically scrap the
blogID and it is represented as blog_id.
Answer: Ah, so now with the code the problem is most likely with
`request.user.username` unfortunately the mezzanine code assumes it is
receiving an ascii object (what `unicode(self)` in the stacktrace is doing)
and is "double encoding" it... grrr!
I would call your method the same way but do this:
call_command(
'import_blogger_hs',
mezzanine_user=request.user.username.decode('utf-8'),
blog_id=blog_id)
Does that fix the issue?
|
UnicodeDecodeError: 'ascii' codec can't decode byte 0xec in position
Question: When I am programming in Ubuntu with python2.7 and MySQLdb, I had an error
when I use other languages in python. English only doesn't make this error.
Traceback (most recent call last):
File "crawl.py", line 242, in <module>
parseArticle( u )
File "crawl.py", line 146, in parseArticle
gatherNeighborInfo( soup )
File "crawl.py", line 69, in gatherNeighborInfo
db.updateURL( url , '자신의 글 주소들을 db에 저장합니다' )
File "crawl.py", line 211, in updateURL self.cursor.execute("UPDATE urls SET state=%d,content='%s' WHERE url='%s'"%(state,content,url))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xec in position 33: ordinal not in range(128)
So i tried to change ascii to utf-8. I made a file named sitecustomize.py on
the /usr/local/lib/python2.7/site-packages. and sitecustomize.py source code
is below.
import sys
sys.setdefaultencoding("utf-8")
but there's nothing changed. please help me. here is the whole source code.
# -*- coding: utf-8 -*-
from bs4 import BeautifulSoup
import robotparser
import urllib2
import time, traceback, re
import MySQLdb
crawler_name = 'daum_blog_crawler'
mainpage = 'http://blog.daum.net/'
# robot parser setting.
rp = robotparser.RobotFileParser( mainpage + 'robots.txt' )
rp.read()
def canFetch( url ):
return rp.can_fetch( crawler_name, url )
def getContent( url, delay=1):
time.sleep( delay )
if not canFetch( url ):
#print 'This url can NOT be fetched by our crawler :', url
return None
try:
opener = urllib2.build_opener()
opener.addheaders = [('User-agent',crawler_name)]
contents = opener.open(url).read()
except:
traceback.print_exc()
return None
return contents
def getArticleInfo( soup ):
rBlog = re.compile('.+blog.daum.net/\w+/\d+.*?')
URLs = soup('a',{'href':rBlog})
return [ u.get('href').split('?')[0] for u in URLs ]
def getOwnArticles( contents ):
ret = []
soup = BeautifulSoup( contents )
rBlog = re.compile('.+/BlogTypeView.+')
for u in soup('a',{'href':rBlog}):
href = u.get('href')
article = href.split('articleno=')[1].split('&')[0]
if ret.count(article)<1:
ret.append( article )
return ret
def gatherNeighborInfo( soup ):
rBlog = re.compile('http://blog.daum.net/\w+')
Neighbors = soup('a',{'href':rBlog})
cnt = 0
for n in Neighbors:
url = n.get('href')
blogname = url.split('/')[-1]
if url and url.startswith('http://') and db.isCrawledURL(url)<1:
db.insertURL( url, 1 )
db.updateURL( url , '자신의 글 주소들을 db에 저장합니다' )
url2 = getRedirectedURL( url )
if not url2: continue
re_url = 'http://blog.daum.net' + url2
body = getContent( re_url, 0 )
if body:
for u in getOwnArticles( body ):
fullpath = 'http://blog.daum.net/'+blogname+'/'+u
cnt+=db.insertURL( fullpath )
if cnt>0: print '%d neighbor articles inserted'%cnt
def getRedirectedURL( url ):
contents = getContent( url )
if not contents: return None
#redirect
try:
soup = BeautifulSoup( contents )
frame = soup('frame')
src = frame[0].get('src')
except:
src = None
return src
def getBody( soup, parent ):
rSrc = re.compile('.+/ArticleContentsView.+')
iframe = soup('iframe',{'src':rSrc})
if len(iframe)>0:
src = iframe[0].get('src')
iframe_src = 'http://blog.daum.net'+src
req = urllib2.Request( iframe_src )
req.add_header('Referer', parent )
body = urllib2.urlopen(req).read()
soup = BeautifulSoup( body )
return str(soup.body)
else:
print 'NULL contents'
return ''
def parseArticle( url ):
article_id = url.split('/')[-1]
blog_id = url.split('/')[-2]
if blog_id.isdigit():
print 'digit:', url.split('/')
newURL = getRedirectedURL( url )
if newURL:
newURL = 'http://blog.daum.net'+newURL
print 'redirecting', newURL
contents = getContent( newURL, 0 )
if not contents:
print 'Null Contents...'
db.updateURL( url, -1 )
return
soup = BeautifulSoup( contents )
gatherNeighborInfo( soup )
n=0
for u in getArticleInfo( soup ):
n+=db.insertURL( u )
if n>0: print 'inserted %d urls from %s'%(n,url)
sp = contents.find('<title>')
if sp>-1:
ep = contents[sp+7:].find('</title>')
title = contents[sp+7:sp+ep+7]
else:
title = ''
contents = getBody( soup, newURL )
pStyle = re.compile('<style(.*?)>(.*?)</style>', re.IGNORECASE | re.MULTILINE | re.DOTALL )
contents = pStyle.sub('', contents)
pStyle = re.compile('<script(.*?)>(.*?)</script>', re.IGNORECASE | re.MULTILINE | re.DOTALL )
contents = pStyle.sub('', contents)
pStyle = re.compile("<(.*?)>", re.IGNORECASE | re.MULTILINE | re.DOTALL )
contents = pStyle.sub("", contents)
db.updateURL( url , '처리했다고 db에 표시합니다.' )
else:
print 'Invalid blog article...'
db.updateURL( url, 'None', -1 )
class DB:
"MySQL wrapper class"
def __init__(self):
self.conn = MySQLdb.connect(db='crawlDB', user='root', passwd='......')
self.cursor = self.conn.cursor()
self.cursor.execute('CREATE TABLE IF NOT EXISTS urls(url CHAR(150), state INT, content TEXT)')
def commit(self):
self.conn.commit()
def __del__(self):
self.conn.commit()
self.cursor.close()
def insertURL(self, url, state=0, content=None):
if url[-1]=='/': url=url[:-1]
try:
self.cursor.execute("INSERT INTO urls VALUES ('%s',%d,'%s')"%(url,state,content))
except:
return 0
else:
return 1
def selectUncrawledURL(self):
self.cursor.execute('SELECT * FROM urls where state=0')
return [ row[0] for row in self.cursor.fetchall() ]
def updateURL(self, url, content, state=1):
if url[-1]=='/': url=url[:-1]
self.cursor.execute("UPDATE urls SET state=%d,content='%s' WHERE url='%s'"%(state,content,url))
def isCrawledURL(self, url):
if url[-1]=='/': url=url[:-1]
self.cursor.execute("SELECT COUNT(*) FROM urls WHERE url='%s' AND state=1"%url)
ret = self.cursor.fetchone()
return ret[0]
db = DB()
if __name__=='__main__':
print 'starting crawl.py...'
contents = getContent( mainpage )
URLs = getArticleInfo( BeautifulSoup( contents ) )
nSuccess = 0
for u in URLs:
nSuccess += db.insertURL( u )
print 'inserted %d new pages.'%nSuccess
while 1:
uncrawled_urls = db.selectUncrawledURL()
if not uncrawled_urls: break
for u in uncrawled_urls:
print 'downloading %s'%u
try:
parseArticle( u )
except:
traceback.print_exc()
db.updateURL( u, -1 )
db.commit()
#bs.UpdateIndex()
Answer: Specify `charset` when connect
self.conn = MySQLdb.connect(db='crawlDB', user='root', passwd='......', charset='utf8')
Replace following line:
self.cursor.execute("UPDATE urls SET state=%d,content='%s' WHERE url='%s'"%(state,content,url))
with (separating the sql from the parameters):
self.cursor.execute("UPDATE urls SET state=%s, content=%s WHERE url=%s", (state,content,url))
Example session:
>>> import MySQLdb
>>> db = MySQLdb.connect('localhost', db='test', charset='utf8')
>>> cursor = db.cursor()
>>> cursor.execute('DROP TABLE IF EXISTS urls')
0L
>>> cursor.execute('CREATE TABLE urls(url char(200), state int, content text)')
0L
>>> cursor.execute('INSERT INTO urls(url, state, content) VALUES(%s, %s, %s)', ('http://daum.net/', 1, u'\uc548\ub155'))
1L
>>> cursor.execute('SELECT * FROM urls')
1L
>>> for row in cursor.fetchall():
... print row
...
(u'http://daum.net/', 1L, u'\uc548\ub155')
|
Cannot print alt and az using pyephem in function
Question: I'm working on building a simple python program for a class which will run on
a Raspberry Pi and an Arduino to direct a telescope. I had started to learn
python some time ago, and I'm having trouble getting my functions to work
properly. Right now, I have this:
import ephem
def const(p, d): # find the constellation #
def loc():
sbend = ephem.Observer()
sbend.lat = '41.67'
sbend.lon = '86.26'
p = getattr(ephem, p)
p.compute(sbend)
print p.alt, p.az
o = getattr(ephem, p)
print ephem.constellation(o(d))
return loc()
const(raw_input('Planet: '), raw_input('yyyy/mm/dd: '))
From what I remember, a function inside another can call a variable from the
parent. Can it also work the other way round like I have at the end? I'd like
to be able to print the constellation (which is working) as well as the alt
and az of the planet based on the hardcoded location. For some reason, it
isn't calculating the altitude and azimuth though. Thoughts?
**EDIT**
I added `return loc()` on line 14.
I was doing more reading and some other threads said that to get to an inner
function, it needs to be returned at the end of the parent. But, it's still
not working for me.
Answer: I am not clear on why you have one function inside of another, so I might be
missing part of the problem that you are trying to solve; but if I wanted to
determine in what constellation a planet lies, where the planet's name and the
date are provided as inputs, then I would simply perform those steps all in a
row, without any complicated functions-inside-of-functions:
import ephem
def const(planet_name, date_string):
planet_class = getattr(ephem, planet_name)
planet = planet_class()
south_bend = ephem.Observer()
south_bend.lat = '41.67'
south_bend.lon = '-86.26' # west is negative
south_bend.date = date_string
planet.compute(south_bend)
return ephem.constellation((planet.ra, planet.dec))
print const(raw_input('Planet: '), raw_input('yyyy/mm/dd: '))
|
How function is getting called without defining in python
Question: Here is the program:
import sys
def IndexSearchString():
'''
This function search a string in a password file through index and gives the result.
:return: none
:return type: none
:author: Neeraj
'''
fieldindex = int(sys.argv[1])-1
stringsrch = sys.argv[2]
file_name = open("passwd", "r")
for store_file in file_name:
temp = store_file.split(":")
search = temp[fieldindex]
#print search
if stringsrch in search:
print store_file
#print sys.stdout.write(store_file)
return
#IndexSearchString()
Answer: Make sure your code is exactly as it is now in the question (including the
edit by @Haidro)
The code, as you pasted it in the question, suggests your indentation was
something like this:
def my_function():
'''
docstring
'''
code_intended_for_my_function()
#my_function()
This would cause `code_intended_for_my_function` to be executed. This is
"valid" because the `docstring` makes the definition for `my_fuction` valid
(it just does nothing), then immediately executes
`code_intended_for_my_function`. To test this, in the code you have, remove
the `docstring` and check if you get an `IndentationError`, or just copy the
code as it is currently from the question and see if it works as you expect.
|
google app engine python hello world application not displaying any thing on the localhost:8080
Question: I ran the following hello world code in python but localhost:8080 doesnot
print anything
i'm using ubuntu 12.04
localhost:8080 shows a blank page
helloworld.py
import webapp2
class MainPage(webapp2.RequestHandler):
def get(self):
self.response.headers['Content-Type'] = 'text/plain'
self.response.write('Hello, World!')
application = webapp2.WSGIApplication([
('/', MainPage),
], debug=True)
app.yaml
application: your-app-id
version: 1
runtime: python27
api_version: 1
threadsafe: true
handlers:
- url: /.*
script: helloworld.application
output is as follows
kiran@kiru-Lenovo-G480:~/google$ dev_appserver.py helloworld/
INFO 2013-10-09 12:22:03,559 sdk_update_checker.py:245] Checking for updates to the SDK.
INFO 2013-10-09 12:22:03,565 __init__.py:94] Connecting through tunnel to: appengine.google.com:443
INFO 2013-10-09 12:22:03,571 sdk_update_checker.py:261] Update check failed: <urlopen error Tunnel connection failed: 407 Proxy Authentication Required>
INFO 2013-10-09 12:22:03,595 api_server.py:138] Starting API server at: http://localhost:44748
INFO 2013-10-09 12:22:03,610 dispatcher.py:168] Starting module "default" running at: http://localhost:8080
INFO 2013-10-09 12:22:03,614 admin_server.py:117] Starting admin server at: http://localhost:8000
Answer: You are calling `write` directly on the `Response` object. You'll want to do
something like this instead:
self.response.out.write('Hello, World!')
|
How to open a file on mac OSX 10.8.2 in python
Question: I am writing a python code on eclipse and want to open a file that is present
in Downloads folder. I am using MAC OSX 10.8.2. I tried with
`f=os.path.expanduser("~/Downloads/DeletingDocs.txt")` and also with
ss=subprocess.Popen("~/Downloads/DeletingDocs.txt",shell=True)
ss.communicate()
I basically want to open a file in subprocess, to listen to the changes in the
opened file.But, the file is not opening in either case.
Answer:
from os.path import baspath, expanduser
filepath = abspath(expanduser("~/") + '/Downloads/DeletingDocs.txt')
print('Opening file', filepath)
with open(filepath, 'r') as fh:
print(fh.read())
Take note of OSX file-handling tho, the IO is a bit different depending on the
filetype. For instance, a `.txt` file which under Windows would be considered
a "plain text-file" is actually a compressed data-stream under OSX because OSX
tries to be "smart" about the storage space.
This can literately ruin your day unless you know about it (been there, had
the headache.. moved on)
When double-clicking on a `.txt` file in OSX for instance normally the text-
editor pops up and what it does is call for a `os.open()` instead of accessing
it on a lower level which lets OSX middle layers do `disk-area|decompression
pipe|file-handle -> Texteditor` but if you access the file-object on a lower
level you'll end up opening the disk-area where the file is stored and if you
print the data you'll get garbage because it's not the data you'd expect.
So try using:
import os
fd = os.open( "foo.txt", os.O_RDONLY )
print(os.read(fd, 1024))
os.close( fd )
And fiddle around with the flags. I honestly can't remember which of the two
opens the file as-is from disk (`open()` or `os.open()`) but one of them makes
your data look like garbage and sometimes you just get the pointer to the
decompression pipe (giving you like 4 bytes of data even tho the text-file is
hughe).
# If it's tracking/catching updates on a file you want
from time import ctime
from os.path import getmtime, expanduser, abspath
from os import walk
for root, dirs, files in walk(expanduser('~/')):
for fname in files:
modtime = ctime(getmtime(abspath(root + '/' + fname)))
print('File',fname,'was last modified at',modtime)
And if the time differs from your last check, well then do something cool with
it. For instance, you have these libraries for Python to work with:
* [.csv](http://docs.python.org/2/library/csv.html)
* [.pdf](http://pybrary.net/pyPdf/)
* [.odf](https://pypi.python.org/pypi/odfpy)
* [.xlsx](https://pypi.python.org/pypi/XlsxWriter)
And MANY more, so instead of opening an external application as your first
fix, try opening them via Python and modify to your liking instead, and only
as a last resort (if even then) open external applications via Popen.
But since you requested it (sort of... erm), here's a **Popen approach** :
from subprocess import Popen, PIPE, STDOUT
from os.path import abspath, expanduser
from time import sleep
run = Popen('open -t ' + abspath(expanduser('~/') + '/example.txt'), shell=True, stdout=PIPE, stdin=PIPE, stderr=STDOUT)
##== Here's an example where you could interact with the process:
##== run.stdin.write('Hey you!\n')
##== run.stdin.flush()
while run.poll() == None:
sleep(1)
# Over-explaining your job:
This will print a files contents every time it's changed.
with open('test.txt', 'r') as fh:
import time
while 1:
new_data = fh.read()
if len(new_data) > 0:
fh.seek(0)
print(fh.read())
time.sleep(5)
**How it works:** The regular file opener `with open() as fh` will open up the
file and place it as a handle in `fh`, once you call `.read()` without any
parameters it will fetch the entire contents of the file. This in turn doesn't
close the file, it simply places the "reading" pointer at the back of the file
(lets say at position 50 for convenience).
So now your pointer is at character 50 in your file, at the end. Wherever you
write something in your file, that will put more data into it so the next
`.read()` will fetch data from position 50+ making the `.read()` not empty, so
we place the "reading" pointer back to position 0 by issuing `.seek(0)` and
then we print all the data.
**Combine that with`os.path.getmtime()`** to fine any reversed changes or 1:1
ratio changes (replacing a character mis-spelling etc).
|
Why aren't my tables available during Django unitests?
Question: When I try to run my unittests, I'm getting an error that says a table is not
available in the database. My tests were running fine a day ago, and a
brainstorm around what I've changed since then isn't bringing to mind anything
that gets close to causing this issue.
I'm seeing this as a problem with `syncdb` and `South` not creating the table
properly in the `sqlite` database, and have tried to troubleshoot around that.
## Error message with traceback
$ ./manage.py test --settings=settings.test -v2
Creating test database for alias 'default' (':memory:')...
Syncing...
Creating tables ...
Creating table django_admin_log
Creating table auth_permission
Creating table auth_group_permissions
Creating table auth_group
Creating table django_content_type
Creating table django_session
Creating table django_site
Creating table south_migrationhistory
Installing custom SQL ...
Installing indexes ...
Synced:
> grappelli
> django.contrib.admin
> django.contrib.admindocs
> django.contrib.auth
> django.contrib.contenttypes
> django.contrib.messages
> django.contrib.sessions
> django.contrib.sites
> django.contrib.staticfiles
> crispy_forms
> floppyforms
> south
> subdomains
> widget_tweaks
Not synced (use migrations):
- apps.application
- apps.app_app
- apps.accounts
- apps.rampup
- apps.students
- apps.automated_responses
(use ./manage.py migrate to migrate these)
======================================================================
ERROR: test_can_save_form_with_clean_passwords (apps.accounts.tests.test_admin.TestCreateUserForm)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/Users/chaz/dev/projects/si/apps/accounts/tests/test_admin.py", line 17, in setUp
self.user = SIDummyUserFactory.create()
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/factory/base.py", line 452, in create
attrs = cls.attributes(create=True, extra=kwargs)
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/factory/base.py", line 316, in attributes
force_sequence=force_sequence,
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/factory/containers.py", line 263, in build
sequence = self.factory._generate_next_sequence()
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/factory/base.py", line 287, in _generate_next_sequence
cls._next_sequence = cls._setup_next_sequence()
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/factory/django.py", line 71, in _setup_next_sequence
).order_by('-pk')[0]
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/models/query.py", line 231, in __getitem__
return list(qs)[0]
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/models/query.py", line 108, in __len__
self._result_cache.extend(self._iter)
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/models/query.py", line 1140, in iterator
for row in self.query.get_compiler(self.db).results_iter():
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 775, in results_iter
for rows in self.execute_sql(MULTI):
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 840, in execute_sql
cursor.execute(sql, params)
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 366, in execute
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
File "/Users/chaz/dev/envs/startupinst/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 362, in execute
return Database.Cursor.execute(self, query, params)
DatabaseError: no such table: accounts_siuser
## Relevent settings
### INSTALLED_APPS
In [2]: settings.INSTALLED_APPS
Out[2]:
('grappelli',
'django.contrib.admin',
'django.contrib.admindocs',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.messages',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.staticfiles',
'crispy_forms',
'floppyforms',
'south',
'subdomains',
'widget_tweaks',
'gunicorn',
'apps.application',
'apps.app_app',
'apps.automated_responses',
'apps.accounts',
'apps.rampup',
'apps.students',
'utils.context_processors',
'discover_runner')
### `pip freeze --local`
Django==1.5.4
Pygments==1.6
South==0.7.6
argparse==1.2.1
bpython==0.12
coverage==3.6
dj-database-url==0.2.1
django-braces==1.2.2
django-crispy-forms==1.2.2
django-debug-toolbar==0.9.4
django-discover-runner==0.4
django-filepicker==0.1.4
django-floppyforms==1.1
django-grappelli==2.4.4
django-parsley==0.0.2a0
django-subdomains==2.0.1
django-templated-email==0.4.7
django-widget-tweaks==1.1.2
envoy==0.0.2
factory-boy==2.1.1
gunicorn==0.16.1
ipdb==0.7
ipython==0.13.2
psycopg2==2.4.5
pytz==2013b
requests==2.0.0
simplejson==3.3.1
six==1.4.1
stripe==1.7.7
zulip==0.2.1
## settings/test.py
""" Test settings and globals which allow us to write our tests locally."""
from .common import *
########
# APPS #
########
INSTALLED_APPS += (
'discover_runner',
)
#################
# TEST SETTINGS #
#################
#TEST_RUNNER = 'django_pytest.test_runner.TestRunner'
TEST_RUNNER = "discover_runner.DiscoverRunner"
TEST_DISCOVER_TOP_LEVEL = PROJECT_ROOT
TEST_DISCOVER_PATTERN = "test_*"
SOUTH_TESTS_MIGRATE = False
###########################
# IN MEMORY TEST DATABASE #
###########################
DATABASES = {
"default": {
"ENGINE": "django.db.backends.sqlite3",
"NAME": ":memory:",
},
}
## Similar SO questions that didn't solve the problem
* [Does South foul up the Django test runner framework](http://stackoverflow.com/questions/6900007/does-south-foul-up-the-django-test-runner-framework)
* [Disable South when running Django unit tests](http://stackoverflow.com/questions/5798446/disable-django-south-when-running-unit-tests)
* [Missing table when running django unittest with sqlite2](http://stackoverflow.com/questions/7336130/missing-table-when-running-django-unittest-with-sqlite3)
## What I've tried so far
* Running the tests on another branch, that wasn't changed during the time when this happened _Result: Getting the same exact error and trackback_
* Blowing away my virtual environment and starting a new one
_Result: No change_
Answer: I ended up removing `South` from my `settings/test.py` file*, and the database
was created properly. Would love to hear if anybody has any ideas about why
this was happening. The setting below should have disabled South, causing
Django's `syncdb` to create the proper tables.
SOUTH_TESTS_MIGRATE = False
SOUTH_SKIP_TESTS = True
*I have settings files for each environment, so just put South in the ones that need it, instead of having it in the `base.py`, which is where they all inherit from.
|
Stepping through date in Python
Question: Let's say I have a starting date of `datetime(2007, 2, 15)`.
I want to step this date in a loop so that it's advanced to the 1st and 15th
of each month.
So `datetime(2007, 2, 15)` would step to `datetime(2007, 3, 1)`.
In the next iteration, it would step to `datetime(2007, 3, 15)`... then to
`datetime(2007, 4, 1)` and so forth.
Is there any possible way to do this with `timedelta` or `dateutils`
considering that, the number of days it has to step by, continuously changes?
Answer:
from datetime import datetime
for m in range(1, 13):
for d in (1, 15):
print str(datetime(2013, m, d))
2013-01-01 00:00:00
2013-01-15 00:00:00
2013-02-01 00:00:00
2013-02-15 00:00:00
2013-03-01 00:00:00
2013-03-15 00:00:00
2013-04-01 00:00:00
2013-04-15 00:00:00
2013-05-01 00:00:00
2013-05-15 00:00:00
2013-06-01 00:00:00
2013-06-15 00:00:00
2013-07-01 00:00:00
2013-07-15 00:00:00
2013-08-01 00:00:00
2013-08-15 00:00:00
2013-09-01 00:00:00
2013-09-15 00:00:00
2013-10-01 00:00:00
2013-10-15 00:00:00
2013-11-01 00:00:00
2013-11-15 00:00:00
2013-12-01 00:00:00
2013-12-15 00:00:00
I tend to work with datetime more than date objects, but you could use
datetime.date depending on your needs.
|
Selenium - Drag and Drop
Question: I am looking to automate the dropping of a file from the desktop to the page
using Firefox as the browser, and Selenium on Python for automation.
Here is the code for the drag-and-drop on the page:
<div id="dropbox">...</div>
<script type="text/javascript"> ...
dropbox.addEventListener("drop", dropUpload, false);
<script>
...
function dropUpload(event) {
...
files = event.dataTransfer.files;
...
}
Most of the threads out there deal with dropping some other element besides a
file from the filesystem. The problem is that I need the event to contain a
file object with the actual data.
I've tried just typing into the dropbox element, as others have suggested, but
this obviously doesn't work with a div element.
Answer: This is very painful to do with Selenium alone. If using a commercial add-on
to Selenium is an option for you, you can try [Helium](http://heliumhq.com).
It lets you drag your file via the following code:
from helium.api import drag_file
drag_file(r"C:\Documents\notes.txt", to=driver.find_element_by_id("dropbox"))
Nicer still is if your `#dropbox` div contains some text, eg. `Drop files
here`. Then you can do
drag_file(r"C:\Documents\notes.txt", to="Drop files here")
|
Python TkInter Button Command Return
Question: I'm having trouble returning a variable from a TkInter button command. This
here is my code:
class trip_calculator:
def gui(self):
returned_values = {}
def open_file_dialog():
returned_values['filename'] = askopenfilename()
root = Tk()
Button(root, text='Browse', command= open_file_dialog).pack()
filepath = returned_values.get('filename')
root.mainloop()
return filepath
root.quit()
I just want to return the filepath of a TXT file. The TkInter window is open
and I can browse and choose the file but it then doesn't return the path. I'm
going nuts!
def __init__(self):
file = self.gui()
Any ideas? Thanks a bunch!
Answer: The way your code is now, `filepath` is assigned its value before your window
even appears to the user. So there's no way the dictionary could contain the
filename that the user eventually selects. The easiest fix is to put `filepath
= returned_values.get('filename')` after `mainloop`, so it won't be assigned
until mainloop ends when the user closes the window.
from Tkinter import *
from tkFileDialog import *
class trip_calculator:
def gui(self):
returned_values = {}
def open_file_dialog():
returned_values['filename'] = askopenfilename()
root = Tk()
Button(root, text='Browse', command= open_file_dialog).pack()
root.mainloop()
filepath = returned_values.get('filename')
return filepath
root.quit()
print(trip_calculator().gui())
|
trouble installing pycurl on mac 10.8.5
Question: I really have trouble installing pycurl on the mac of my girlfriend, I managed
to do it on my own but I did not remember which command brought the success.
Everything I tried on her mac wont't work.
I looked up every answer I could find on how to install pycurl, nothing worked
for me :(. I tried macports, didn't work as well. The problem is, I am not
that into using the terminal
Here is what I've tried so far:
sudo port install py27-yaml
sudo port install py27-curl
/opt/local/bin/python2.7
import pycurl
but id didn't ' work :(
trying `sudo env ARCHFLAGS="-arch x86_64" easy_install setuptools
pycurl==7.19.0`
brings me this
Last login: Wed Oct 9 23:51:34 on ttys000
Loras-MacBook-Air:~ Lora$ sudo env ARCHFLAGS="-arch x86_64" easy_install setuptools pycurl==7.19.0
Searching for setuptools
Best match: setuptools 0.6c12dev-r88846
setuptools 0.6c12dev-r88846 is already the active version in easy-install.pth
Installing easy_install script to /usr/local/bin
Installing easy_install-2.7 script to /usr/local/bin
Using /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
Processing dependencies for setuptools
Finished processing dependencies for setuptools
Searching for pycurl==7.19.0
Reading http://pypi.python.org/simple/pycurl/
Reading http://pycurl.sourceforge.net/
Reading http://pycurl.sourceforge.net/download/
Best match: pycurl 7.19.0
Downloading http://pycurl.sourceforge.net/download/pycurl-7.19.0.tar.gz
Processing pycurl-7.19.0.tar.gz
Running pycurl-7.19.0/setup.py -q bdist_egg --dist-dir /tmp/easy_install-r7sdRe/pycurl-7.19.0/egg-dist-tmp-DKaHyW
Using curl-config (libcurl 7.32.0)
clang: warning: argument unused during compilation: '-mno-fused-madd'
src/pycurl.c:1168:16: warning: implicit conversion loses integer precision:
'long' to 'int' [-Wshorten-64-to-32]
ret = dup(PyInt_AsLong(fileno_result));
~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~
src/pycurl.c:1912:31: warning: implicit conversion loses integer precision:
'long' to 'int' [-Wshorten-64-to-32]
val = PyLong_AsLong(PyTuple_GET_ITEM(t, j));
~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/pycurl.c:2904:22: warning: implicit conversion loses integer precision:
'long' to '__darwin_suseconds_t' (aka 'int') [-Wshorten-64-to-32]
tv.tv_usec = (long)(timeout*1000000.0);
~ ^~~~~~~~~~~~~~~~~~~~~~~~~
3 warnings generated.
zip_safe flag not set; analyzing archive contents...
Adding pycurl 7.19.0 to easy-install.pth file
Installed /Library/Python/2.7/site-packages/pycurl-7.19.0-py2.7-macosx-10.8-x86_64.egg
Processing dependencies for pycurl==7.19.0
Finished processing dependencies for pycurl==7.19.0
Loras-MacBook-Air:~ Lora$
i just cant get i done :(
Answer: The Apple LLVM compiler in Xcode 5.1 treats unrecognized command-line options
as errors. This issue has been seen when building both Python native
extensions and Ruby Gems, where some invalid compiler options are currently
specified. from [Kasper Munck](http://kaspermunck.github.io/2014/03/fixing-
clang-error/)
sudo ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future easy_install-2.7 pycurl
|
Python: Dynamically Update Array Cells from Parent Program
Question: I previously asked a question about updating a single value in a parallel
process from a parent program. Great answers to this can be found at [Python:
Update Local Variable in a Parallel Process from Parent
Program](http://stackoverflow.com/questions/19233246/python-update-local-
variable-in-a-parallel-process-from-parent-
program/19234437?noredirect=1#19234437). Now I would like to extend this
question to arrays. Say I have the following simple program that iterates
through the first cell of an defined array (similar to the link provided):
import time
def loop(i):
while 1:
print i[0]
i[0] += 1
time.sleep(1)
if __name__ == "__main__":
from multiprocessing import Process, Array
i = Array("i", [1,2,3,4])
p = Process(target=loop, args=(i,))
p.start()
time.sleep(2)
# update i in shared memory???
From this program, how can I update "i" so the "loop" function continues to
run and reads the new array? For example, if I want to set "i" to
[50,51,52,53]. Is there an equivalent attribute like "value" that can do this?
I did much searching around and could not find any solutions. Thank you very
much in advance.
Answer: To update `i` _in-place_ use
i[:] = [50, 51, 52,53]
Note that it is important that you modify `i` in-place because if you were to
assign `i` to a new value, such as by using
i = [50, 51, 52, 53]
Then `i` would simply point to a new list, without modifying the shared array.
The Python idiom `i[:] = [...]` is also used for modifying Python lists in-
place, by the way.
* * *
import time
def loop(i):
while 1:
print list(i)
# i[0] += 1
i[:] = [50,51,52,53]
time.sleep(1)
if __name__ == "__main__":
from multiprocessing import Process, Array
i = Array("i", [1,2,3,4])
p = Process(target=loop, args=(i,))
p.start()
|
Python3 Qt unicode file name problems
Question: Similar to
[QDir and QDirIterator ignore files with non-ASCII
filenames](http://stackoverflow.com/questions/1641994/qdir-and-qdiriterator-
ignore-files-with-non-ascii-filenames)
and
[UnicodeEncodeError: 'latin-1' codec can't encode
character](http://stackoverflow.com/questions/3942888/unicodeencodeerror-
latin-1-codec-cant-encode-character)
With regard to the second link above, I added test0() below. My understanding
was that utf-8 was the solution I was searching for, but alas trying to encode
the filename fails.
def test0():
print("test0...using unicode literal")
name = u"123c\udcb4.wav"
test("test0b", name)
n = name.encode('utf-8')
print(n)
n = QtCore.QFile.decodeName(n)
print(n)
# From http://docs.python.org/release/3.0.1/howto/unicode.html
# This will indeed overwrite the correct file!
# f = open(name, 'w')
# f.write('blah\n')
# f.close()
Test0 results...
test0...using unicode literal
test0b QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test0b QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test0b os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test0b os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
Traceback (most recent call last):
File "unicode.py", line 157, in <module>
test0()
File "unicode.py", line 42, in test0
n = name.encode('utf-8')
UnicodeEncodeError: 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed
**EDIT**
Further reading from <http://tools.ietf.org/html/rfc3629> tells me that "The
definition of UTF-8 prohibits encoding character numbers between U+D800 and
U+DFFF". So if uft-8 doesn't allow these characters. How are you supposed to
deal with a file that is so named? Python can create and test existence for
them. So this points me at an issue with my Qt api usage or the Qt api
itself?!
I am struggling to wrap my head around proper handling of unicode file name in
Python3. Ultimately, I'm working on a Phonon based music player. I've tried to
isolate the problem(s) from that as much as possible. From the code below you
will see that I've tried as many alternatives as I can find. My initial
response is that there are bugs here....maybe mine...maybe in one or more
libraries. Any help would be much appreciated!
I have a directory with 3 unicode file names 123[abc]U.wav. The first 2 files
are handled properly...mostly...the third one 123c is just wrong.
from PyQt4 import QtGui, QtCore
import sys, os
def test(_name, _file):
# print(_name, repr(_file))
f = QtCore.QFile(_file)
# f = QtCore.QFile(QtCore.QFile.decodeName(test))
exists = f.exists()
try:
print(_name, "QFile.exists", f.fileName(), exists)
except UnicodeEncodeError as e:
print(e, repr(_file), exists)
fileInfo = QtCore.QFileInfo(_file)
exists = fileInfo.exists()
try:
print(_name, "QFileInfo.exists", fileInfo.fileName(), exists)
except UnicodeEncodeError as e:
print(e, repr(_file), exists)
exists = os.path.exists(_file)
try:
print(_name, "os.path.exists", _file, exists)
except UnicodeEncodeError as e:
print(e, repr(_file), exists)
exists = os.path.isfile(_file)
try:
print(_name, "os.path.isfile", _file, exists)
except UnicodeEncodeError as e:
print(e, repr(_file), exists)
print()
def test1():
args = QtGui.QApplication.arguments()
print("test1...using QtGui.QApplication.arguments()")
test("test1", args[1])
def test2():
print("test2...using sys.argv")
test("test2", sys.argv[1])
def test3():
print("test3...QtGui.QFileDialog.getOpenFileName()")
name = QtGui.QFileDialog.getOpenFileName()
test("test3", name)
def test4():
print("test4...QtCore.QDir().entryInfoList()")
p = os.path.abspath(__file__)
p, _ = os.path.split(p)
d = QtCore.QDir(p)
for inf in d.entryInfoList(QtCore.QDir.AllEntries|QtCore.QDir.NoDotAndDotDot|QtCore.QDir.System):
print("test4", inf.fileName())
# if str(inf.fileName()).startswith("123c"):
if u"123c\ufffd.wav" == inf.fileName():
# if u"123c\udcb4.wav" == inf.fileName(): # This check fails..even tho that is what is reported in error messages for test2
test("test4a", inf.fileName())
test("test4b", inf.absoluteFilePath())
def test5():
print("test5...os.listdir()")
p = os.path.abspath(__file__)
p, _ = os.path.split(p)
dirList = os.listdir(p)
for file in dirList:
fullfile = os.path.join(p, file)
try:
print("test5", file)
except UnicodeEncodeError as e:
print(e)
print("test5", repr(fullfile))
# if u"123c\ufffd.wav" == file: # This check fails..even tho it worked in test4
if u"123c\udcb4.wav" == file:
test("test5a", file)
test("test5b", fullfile)
print()
def test6():
print("test6...Phonon and QtGui.QFileDialog.getOpenFileName()")
from PyQt4.phonon import Phonon
class Window(QtGui.QDialog):
def __init__(self):
QtGui.QDialog.__init__(self, None)
self.mediaObject = Phonon.MediaObject(self)
self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self)
Phonon.createPath(self.mediaObject, self.audioOutput)
self.mediaObject.stateChanged.connect(self.handleStateChanged)
name = QtGui.QFileDialog.getOpenFileName()# works with python3..not for 123c
# name = QtGui.QApplication.arguments()[1] # works with python2..but not python3...not for 123c
# name = sys.argv[1] # works with python3..but not python2...not for 123c
# p = os.path.abspath(__file__)
# p, _ = os.path.split(p)
# print(p)
# name = os.path.join(p, str(name))
self.mediaObject.setCurrentSource(Phonon.MediaSource(name))
self.mediaObject.play()
def handleStateChanged(self, newstate, oldstate):
if newstate == Phonon.PlayingState:
source = self.mediaObject.currentSource().fileName()
print('test6 playing: :', source)
elif newstate == Phonon.StoppedState:
source = self.mediaObject.currentSource().fileName()
print('test6 stopped: :', source)
elif newstate == Phonon.ErrorState:
source = self.mediaObject.currentSource().fileName()
print('test6 ERROR: could not play:', source)
win = Window()
win.resize(200, 100)
# win.show()
win.exec_()
def timerTick():
QtGui.QApplication.exit()
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
app.setApplicationName('unicode_test')
test1()
test2()
test3()
test4()
test5()
test6()
timer = QtCore.QTimer()
timer.timeout.connect(timerTick)
timer.start(1)
sys.exit(app.exec_())
Test results with 123a...
python3 unicode.py 123a�.wav
test1...using QtGui.QApplication.arguments()
test1 QFile.exists unknown False
test1 QFileInfo.exists unknown False
test1 os.path.exists unknown False
test1 os.path.isfile unknown False
test2...using sys.argv
test2 QFile.exists 123a�.wav True
test2 QFileInfo.exists 123a�.wav True
test2 os.path.exists 123a�.wav True
test2 os.path.isfile 123a�.wav True
test3...QtGui.QFileDialog.getOpenFileName()
test3 QFile.exists /home/mememe/Desktop/test/unicode/123a�.wav True
test3 QFileInfo.exists 123a�.wav True
test3 os.path.exists /home/mememe/Desktop/test/unicode/123a�.wav True
test3 os.path.isfile /home/mememe/Desktop/test/unicode/123a�.wav True
test4...QtCore.QDir().entryInfoList()
test4 123a�.wav
test4 123bÆ.wav
test4 123c�.wav
test4a QFile.exists 123c�.wav False
test4a QFileInfo.exists 123c�.wav False
test4a os.path.exists 123c�.wav False
test4a os.path.isfile 123c�.wav False
test4b QFile.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test4b QFileInfo.exists 123c�.wav False
test4b os.path.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test4b os.path.isfile /home/mememe/Desktop/test/unicode/123c�.wav False
test4 unicode.py
test5...os.listdir()
test5 unicode.py
test5 '/home/mememe/Desktop/test/unicode/unicode.py'
test5 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed
test5 '/home/mememe/Desktop/test/unicode/123c\udcb4.wav'
test5a QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test5a QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test5a os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test5a os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test5b QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' False
test5b QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' False
test5b os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' True
test5b os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' True
test5 123bÆ.wav
test5 '/home/mememe/Desktop/test/unicode/123bÆ.wav'
test5 123a�.wav
test5 '/home/mememe/Desktop/test/unicode/123a�.wav'
test6...Phonon and QtGui.QFileDialog.getOpenFileName()
test6 stopped: : /home/mememe/Desktop/test/unicode/123a�.wav
test6 playing: : /home/mememe/Desktop/test/unicode/123a�.wav
test6 stopped: : /home/mememe/Desktop/test/unicode/123a�.wav
Test results with 123b...
python3 unicode.py 123bÆ.wav
test1...using QtGui.QApplication.arguments()
test1 QFile.exists 123b.wav False
test1 QFileInfo.exists 123b.wav False
test1 os.path.exists 123b.wav False
test1 os.path.isfile 123b.wav False
test2...using sys.argv
test2 QFile.exists 123bÆ.wav True
test2 QFileInfo.exists 123bÆ.wav True
test2 os.path.exists 123bÆ.wav True
test2 os.path.isfile 123bÆ.wav True
test3...QtGui.QFileDialog.getOpenFileName()
test3 QFile.exists /home/mememe/Desktop/test/unicode/123bÆ.wav True
test3 QFileInfo.exists 123bÆ.wav True
test3 os.path.exists /home/mememe/Desktop/test/unicode/123bÆ.wav True
test3 os.path.isfile /home/mememe/Desktop/test/unicode/123bÆ.wav True
test4...QtCore.QDir().entryInfoList()
test4 123a�.wav
test4 123bÆ.wav
test4 123c�.wav
test4a QFile.exists 123c�.wav False
test4a QFileInfo.exists 123c�.wav False
test4a os.path.exists 123c�.wav False
test4a os.path.isfile 123c�.wav False
test4b QFile.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test4b QFileInfo.exists 123c�.wav False
test4b os.path.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test4b os.path.isfile /home/mememe/Desktop/test/unicode/123c�.wav False
test4 unicode.py
test5...os.listdir()
test5 unicode.py
test5 '/home/mememe/Desktop/test/unicode/unicode.py'
test5 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed
test5 '/home/mememe/Desktop/test/unicode/123c\udcb4.wav'
test5a QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test5a QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test5a os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test5a os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test5b QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' False
test5b QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' False
test5b os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' True
test5b os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' True
test5 123bÆ.wav
test5 '/home/mememe/Desktop/test/unicode/123bÆ.wav'
test5 123a�.wav
test5 '/home/mememe/Desktop/test/unicode/123a�.wav'
test6...Phonon and QtGui.QFileDialog.getOpenFileName()
test6 stopped: : /home/mememe/Desktop/test/unicode/123bÆ.wav
test6 playing: : /home/mememe/Desktop/test/unicode/123bÆ.wav
test6 stopped: : /home/mememe/Desktop/test/unicode/123bÆ.wav
Test results with 123c...
python3 unicode.py 123c�.wav
test1...using QtGui.QApplication.arguments()
test1 QFile.exists unknown False
test1 QFileInfo.exists unknown False
test1 os.path.exists unknown False
test1 os.path.isfile unknown False
test2...using sys.argv
test2 QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test2 QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test2 os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test2 os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test3...QtGui.QFileDialog.getOpenFileName()
test3 QFile.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test3 QFileInfo.exists 123c�.wav False
test3 os.path.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test3 os.path.isfile /home/mememe/Desktop/test/unicode/123c�.wav False
test4...QtCore.QDir().entryInfoList()
test4 123a�.wav
test4 123bÆ.wav
test4 123c�.wav
test4a QFile.exists 123c�.wav False
test4a QFileInfo.exists 123c�.wav False
test4a os.path.exists 123c�.wav False
test4a os.path.isfile 123c�.wav False
test4b QFile.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test4b QFileInfo.exists 123c�.wav False
test4b os.path.exists /home/mememe/Desktop/test/unicode/123c�.wav False
test4b os.path.isfile /home/mememe/Desktop/test/unicode/123c�.wav False
test4 unicode.py
test5...os.listdir()
test5 unicode.py
test5 '/home/mememe/Desktop/test/unicode/unicode.py'
test5 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed
test5 '/home/mememe/Desktop/test/unicode/123c\udcb4.wav'
test5a QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test5a QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' False
test5a os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test5a os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '123c\udcb4.wav' True
test5b QFile.exists 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' False
test5b QFileInfo.exists 'utf-8' codec can't encode character '\udcb4' in position 4: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' False
test5b os.path.exists 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' True
test5b os.path.isfile 'utf-8' codec can't encode character '\udcb4' in position 38: surrogates not allowed '/home/mememe/Desktop/test/unicode/123c\udcb4.wav' True
test5 123bÆ.wav
test5 '/home/mememe/Desktop/test/unicode/123bÆ.wav'
test5 123a�.wav
test5 '/home/mememe/Desktop/test/unicode/123a�.wav'
test6...Phonon and QtGui.QFileDialog.getOpenFileName()
test6 stopped: : /home/mememe/Desktop/test/unicode/123c�.wav
Interesting things to note about the test results...
* Test1 failed for all 3 files.
* Test2 passed for all 3 files...except for the QFile and QFileInfo tests for 123c
* Test3 passed for 123a and 123b but failed for 123c
* Test4 ...QDir found all 4 files in the directory
* Test4a and Test4b failed for all files
* Test5 ...os.listdir found all 4 files in the directory
* NOTE: The Test5a and test5b checks had to use a different unicode check?!
* Test5a and Test5b failed the QFile and QfileInfo tests, but passed the os.path checks.
* Test6 passed for 123a and 123b, but failed for 123c...the phonon player got a stopped only message vs the stopped playing stopped the 123a and 123b files got.
I know that is a lot of information...I wast trying to be thorough.
So, if there is one final question is what is the right way to deal with
unicode file names in Python3?
Answer: You're right, `123c` is just wrong. The evidence shows that the filename on
disk contains an [invalid Unicode codepoint
U+DCB4](http://www.fileformat.info/info/unicode/char/dcb4/index.htm). When
Python tries to print that character, it rightly complains that it can't. When
Qt processes the character in test4 it can't handle it either, but instead of
throwing an error it converts it to the [Unicode REPLACEMENT CHARACTER
U+FFFD](http://www.fileformat.info/info/unicode/char/fffd/index.htm).
Obviously the new filename no longer matches what's on disk.
Python can also use the replacement character in a string instead of throwing
an error if you do the conversion yourself and specify the proper error
handling. I don't have Python 3 on hand to test this but I think it will work:
filename = filename.encode('utf-8').decode('utf-8', 'replace')
|
Save EACH regex match to a new txt file (batch)?
Question: I basically need a program/script that will search a file for regex matches
and then save each match to a newly created text file (ie. match_01.txt,
match_02.txt, match_03.txt, etc.). NB: it must support multiline matching!
**EDIT :**
This is what I tried using Josha's help (thx:):
I get an error when I try this
**Python Script:**
import re
pattern = re.compile(r'(?s)(?<=Sample)(.*?)(?=EndSample)', flags=re.S)
with open('test.txt', 'r') as f:
matches = pattern.findall(f.read())
for i, match in enumerate(matches):
with open('Split/match{0:04d}.txt'.format(i), 'w') as nf:
nf.write(match)
**Command Prompt:**
C:\Test\python test.py
Traceback (most recent call last):
File "test.py", line 31, in <module>
nf.write(match)
TypeError: expected a character buffer object
test.txt looks something like this:
Sample A1 ... ... ... ... ... EndSample
Sample B4 ... ... ... ... ... EndSample
Sample X6 ... ... ... ... ... EndSample
So I need to match everything between "Sample" and "EndSample" (hundreds of
lines in-between) and write each match to its own txt file. So far it only
works if my regex pattern is ie. "Sample". There is 15 matches and it does
create 15 txt files in the Split folder but they all contain just the word
Sample and nothing more. Multiline still not working looks like.. And if my
regex is this:
> (?s)(Sample)(.*?)
then it also gives me the same error as above. Its like it doesnt like (.*?)
Strange..?
Answer: In Python (assuming matches do not span lines):
import re
pattern = re.compile(r'(?s)(?<=Sample)((?:.+?)?)(?=EndSample)', flags=re.S) # Your regex goes here
with open('path/to/your/file.txt', 'r') as f:
matches = pattern.findall(f.read())
for i, match in enumerate(matches):
with open('/path/to/your/match{0:04d}.txt'.format(i), 'w') as nf:
nf.write(match)
|
Python SetCursorPos error? Or online game cause it?
Question: The code works perfectly with no errors until I unminimize the game.After a
lot of tries to locate why SetCursorPos doesnt work , I understoud that it did
not have a problem with the cords , but it refuses to move to the location
when its on the window of the game. The code so far is:
from PIL import ImageGrab
import os
import time
import win32con , win32api
x_pad = 2
y_pad = 27
def start():
#location of first menu
mousePos((682, 519))
leftClick()
time.sleep(.1)
leftClick()
time.sleep(.5)
#location of second menu
mousePos((1208, 528))
leftClick()
time.sleep(.5)
#location of third menu
mousePos((921, 479))
leftClick()
time.sleep(.5)
#location of fourth menu
mousePos((651, 350))
leftClick()
time.sleep(.5)
def screenGrab():
box = (x_pad+1,y_pad+1,x_pad+1362,y_pad+770)
im = ImageGrab.grab(box)
im.save(os.getcwd() + '\\full_snap__' + str(int(time.time())) +
'.png', 'PNG')
def mousePos(cord):
win32api.SetCursorPos((x_pad + cord[0], y_pad + cord[1]))
def get_cords():
x,y = win32api.GetCursorPos()
x = x - x_pad
y = y - y_pad
print x,y
def leftClick():
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTDOWN,0,0)
time.sleep(.1)
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTUP,0,0)
print "Click."
def main():
pass
if __name__ == "__MAIN__":
main()
And when i run start() i get this:
Python 2.7.5 (default, May 15 2013, 22:43:36) [MSC v.1500 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>>
>>> start()
'Traceback (most recent call last):
File "<pyshell#0>", line 1, in <module>
start()
File "C:\Users\User\Desktop\py\game.py", line 12, in start
mousePos((682, 519))
File "C:\Users\User\Desktop\py\game.py", line 42, in mousePos
win32api.SetCursorPos((x_pad + cord[0], y_pad + cord[1]))
error: (0, 'SetCursorPos', 'No error message is available')'
>>>
I have no idea why this happens and i have tryed many solutions from this site
,could it be the game? What i want to know is if the game is the cause of the
error or I have missed something , and if there is a posible solution.
Answer: are you running through the tutorial from
<http://dev.tutsplus.com/tutorials/how-to-build-a-python-bot-that-can-play-
web-games--active-11117>?
Shouldn't be an issue with it, i went through the same and it worked.
|
how can I get the gap colum in python?
Question: the log format is like that 100 0 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 1
11 1 12 1 13 1 14 1 15 1 16 1 17 1 18 1 19 1 20 1 21 1 22 1 23 1 24 1 25 1 26
1 27 1 28 1 29 1 30 1 31 1 32 1 33 1 34 1 35 1
And I write python code,
def read_data(filename, sep=" ", filt=int):
def split_line(line):
return line.split(sep)
def apply_filt(values):
return map(filt, values)
def process_line(line):
return apply_filt(split_line(line))
f = open(filename)
lines = map(process_line, f.readlines())
# "[1]" below corresponds to x0
X = np.array([ l[3:] for l in lines])
# "or -1" converts 0 values to -1
Y = np.array([l[1] or -1 for l in lines])
f.close()
return X, Y
X are getted from 3 colums,and Now I want to get every gap colum from the
third colums,how can I change the code,and the X will be 1 1 1 1 1 1 1 1 1 1 Y
are getted l[1] or -1.But I want to get 1 if l1 is greater than 0,and get -1
if l1 is equal to 0.How can I change it again?
Answer: I'm going to guess you want something like this:
import numpy as np
try:
from cStringIO import StringIO
except:
from StringIO import StringIO
def read_data(f, sep=" ", filt=int):
def split_line(line):
return line.split(sep)
def apply_filt(values):
return map(filt, values)
def process_line(line):
return apply_filt(split_line(line))
#f = open(filename)
lines = np.array(map(process_line, f.readlines()), dtype=int)
# "[1]" below corresponds to x0
X = lines[:,3::2]
# "or -1" converts 0 values to -1
Y = lines[:,:]
Y[Y<=0]=-1
f.close()
return X, Y
reader = StringIO('100 0 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 1 11 1 12 1 13 1 14 1 15 1 16 1 17 1 18 1 19 1 20 1 21 1 22 1 23 1 24 1 25 1 26 1 27 1 28 1 29 1 30 1 31 1 32 1 33 1 34 1 35 1\n')
x,y = read_data(reader)
reader.close
print 'X:', x
print 'Y:', y
which gives:
X: [[1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1]]
Y: [[100 -1 -1 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1
8 1 9 1 10 1 11 1 12 1 13 1 14 1 15 1 16 1
17 1 18 1 19 1 20 1 21 1 22 1 23 1 24 1 25 1
26 1 27 1 28 1 29 1 30 1 31 1 32 1 33 1 34 1
35 1]]
|
ImportError: No module named redis
Question: I have installed redis using `sudo apt-get install redis-server` command but I
am receiving this error when I run my Python program: `ImportError: No module
named redis`
Any idea what's going wrong or if I should install any other package as well?
I am using Ubuntu 13.04 and I have Python 2.7.
Answer: To install redis-py, simply:
$ sudo pip install redis
or alternatively (you really should be using pip though):
$ sudo easy_install redis
or from source:
$ sudo python setup.py install
Getting Started
>>> import redis
>>> r = redis.StrictRedis(host='localhost', port=6379, db=0)
>>> r.set('foo', 'bar')
True
>>> r.get('foo')
'bar'
Details:<https://pypi.python.org/pypi/redis>
|
wxpython panel size and titles
Question: When I apply the following code, the second panel is showed over the first
one. I would like to know how I can get the two panels without overlapping and
with the appropriate size of the window (frame). I would also like to know if
there is any suitable way to draw some kind of titles in a panel (in this
case, "Inputs:" and "Outputs:"). Thanks!
import wx
class Input_Panel(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
# Input variables
self.tittle1 = wx.StaticText(self, label="Inputs:")
self.lblname1 = wx.StaticText(self, label="Input 1:")
self.format1 = ['Option 1','Option 2']
self.combo1 = wx.ComboBox(self, size=(200, -1),value='', choices=self.format1, style=wx.CB_DROPDOWN)
self.lblname2 = wx.StaticText(self, label="Input 2")
self.format2 = ['Option 1','Option 2', 'Option 3']
self.combo2 = wx.ComboBox(self, size=(200, -1),value='', choices=self.format2, style=wx.CB_DROPDOWN)
# Set sizer for the panel content
self.sizer = wx.GridBagSizer(2, 2)
self.sizer.Add(self.tittle1, (1, 2))
self.sizer.Add(self.lblname1, (2, 1))
self.sizer.Add(self.combo1, (2, 2))
self.sizer.Add(self.lblname2, (3, 1))
self.sizer.Add(self.combo2, (3, 2))
self.SetSizer(self.sizer)
class Output_Panel(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
# Output variables
self.tittle2 = wx.StaticText(self, label="Outputs:")
self.lblname3 = wx.StaticText(self, label="Output1")
self.result3 = wx.StaticText(self, label="", size=(100, -1))
# Set sizer for the panel content
self.sizer = wx.GridBagSizer(2, 2)
self.sizer.Add(self.tittle2, (1, 2))
self.sizer.Add(self.lblname3, (2, 1))
self.sizer.Add(self.result3, (2, 2))
self.SetSizer(self.sizer)
class Main_Window(wx.Frame):
def __init__(self, parent, title):
wx.Frame.__init__(self, parent, title = title)
# Set variable panels
self.splitter = wx.SplitterWindow(self)
self.panel1 = Input_Panel(self.splitter)
self.panel2 = Output_Panel(self.splitter)
self.splitter.SplitVertically(self.panel1, self.panel2)
self.windowSizer = wx.BoxSizer(wx.VERTICAL)
self.windowSizer.Add(self.splitter, 1, wx.ALL | wx.EXPAND)
self.SetSizerAndFit(self.windowSizer)
def main():
app = wx.App(False)
frame = Main_Window(None, "App GUI")
frame.Show()
app.MainLoop()
if __name__ == "__main__" :
main()
Answer: You can use the Widget Inspection Tool to help you figure out what's going on.
I used its highlight functionality to figure out where and what size each of
the panels were. You can read more about it here:
<http://wiki.wxpython.org/Widget%20Inspection%20Tool>
The SplitterWindow does not split items equally. You will need to call the
splitter's SetMinimumPaneSize to make them both visible. I modified your code
to show you what I'm talking about and also to demonstrate how to add the
inspection tool:
import wx
class Input_Panel(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
# Input variables
self.tittle1 = wx.StaticText(self, label="Inputs:")
self.lblname1 = wx.StaticText(self, label="Input 1:")
self.format1 = ['Option 1','Option 2']
self.combo1 = wx.ComboBox(self, size=(200, -1),value='', choices=self.format1, style=wx.CB_DROPDOWN)
self.lblname2 = wx.StaticText(self, label="Input 2")
self.format2 = ['Option 1','Option 2', 'Option 3']
self.combo2 = wx.ComboBox(self, size=(200, -1),value='', choices=self.format2, style=wx.CB_DROPDOWN)
# Set sizer for the panel content
self.sizer = wx.GridBagSizer(2, 2)
self.sizer.Add(self.tittle1, (1, 2))
self.sizer.Add(self.lblname1, (2, 1))
self.sizer.Add(self.combo1, (2, 2))
self.sizer.Add(self.lblname2, (3, 1))
self.sizer.Add(self.combo2, (3, 2))
self.SetSizer(self.sizer)
class Output_Panel(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
# Output variables
self.tittle2 = wx.StaticText(self, label="Outputs:")
self.lblname3 = wx.StaticText(self, label="Output1")
self.result3 = wx.StaticText(self, label="", size=(100, -1))
# Set sizer for the panel content
self.sizer = wx.GridBagSizer(2, 2)
self.sizer.Add(self.tittle2, (1, 2))
self.sizer.Add(self.lblname3, (2, 1))
self.sizer.Add(self.result3, (2, 2))
self.SetSizer(self.sizer)
class Main_Window(wx.Frame):
def __init__(self, parent, title):
wx.Frame.__init__(self, parent, title = title, size=(800,600))
# Set variable panels
self.splitter = wx.SplitterWindow(self, style = wx.SP_LIVE_UPDATE)
self.panel1 = Input_Panel(self.splitter)
self.panel2 = Output_Panel(self.splitter)
self.splitter.SplitVertically(self.panel1, self.panel2)
w, h = self.GetSize()
self.splitter.SetMinimumPaneSize(w/2)
self.windowSizer = wx.BoxSizer(wx.VERTICAL)
self.windowSizer.Add(self.splitter, 1, wx.ALL | wx.EXPAND)
#self.SetSizerAndFit(self.windowSizer)
def main():
import wx.lib.inspection
app = wx.App(False)
frame = Main_Window(None, "App GUI")
frame.Show()
wx.lib.inspection.InspectionTool().Show()
app.MainLoop()
if __name__ == "__main__" :
main()
|
packaging with numpy and test suite
Question: # Introduction
Disclaimer: I'm very new to python packaging with distutils. So far I've just
stashed everything into modules, and packages manually and developed on top of
that. I never wrote a `setup.py` file before.
I have a Fortran module that I want to use in my python code with numpy. I
figured the best way to do that would be f2py, since it is included in numpy.
To automate the build process I want to use distutils and the corresponding
numpy enhancement, which includes convenience functions for f2py wrappers.
I do not understand how I should organize my files, and how to include my test
suite.
What I want is the possibility to use `./setup.py` for building, installing,
and testing, and developing.
My directory structure looks as follows:
volterra
├── setup.py
└── volterra
├── __init__.py
├── integral.f90
├── test
│ ├── __init__.py
│ └── test_volterra.py
└── volterra.f90
And the `setup.py` file contains this:
def configuration(parent_package='', top_path=None):
from numpy.distutils.misc_util import Configuration
config = Configuration('volterra', parent_package, top_path)
config.add_extension('_volterra',
sources=['volterra/integral.f90', 'volterra/volterra.f90'])
return config
if __name__ == '__main__':
from numpy.distutils.core import setup
setup(**configuration(top_path='').todict())
After running `./setup.py build` I get.
build/lib.linux-x86_64-2.7/
└── volterra
└── _volterra.so
Which includes neither the `__init__.py` file, nor the tests.
# Questions
* Is it really necessary to add the path to every single source file of the extension? (I.e. `volterra/integral.f90`) Can't I give a parameter which says, look for stuff in `volterra/`? The `top_path`, and `package_dir` parameters didn't do the trick.
* Currently, the `__init__.py` file is not included in the build. Why is that?
* How can I run my tests in this setup?
* What's the best workflow for doing development in such an environment? I don't want to _install_ my package for every single change I do. How do you do development in the source directory when you need to compile some extension modules?
Answer: Here is setup.py from a project I made. I have found figuring out setup.py /
packaging to be frustrating with no solid answers and definitely not pythonic
in the sense of having one and only one obvious way to do something. Hopefully
this will help a little.
The points you may find useful are:
* `find_packages` which removes the drudgery of including lots of files or messing around with generating manifest.
* `package_data` which allows you to easily specify non .py files to be included
* `install_requires` / `tests_require`
You'll need to find the source for distribute_setup.py if you don't have it
already.
> * Is it really necessary to add the path to every single source file of
> the extension? (I.e. volterra/integral.f90) Can't I give a parameter which
> says, look for stuff in volterra/? The top_path, and package_dir parameters
> didn't do the trick.
> * Currently, the **init**.py file is not included in the build. Why is
> that?
>
Hopefully `find_packages()` will solve both of those. I don't have much
experience packaging but I haven't had to go back to manual inclusion yet.
> * How can I run my tests in this setup?
>
I think this is probably a different question with many answers depending on
how you are doing tests. Maybe you can ask it separately?
As a side note, I am under the impression that the standard is to put your
tests directory at the top level. I.e. `volterra/volterra` and
`volterra/tests`.
> * What's the best workflow for doing development in such an environment? I
> don't want to install my package for every single change I do. How do you do
> development in the source directory when you need to compile some extension
> modules?
>
This might be worth another question as well. I don't see why you would need
to install your package for every single change. If you are uploading the
package, just don't install it on your dev system (except to test
installation) and work directly from your development copy. Maybe I'm missing
something though since I don't work with compiled extensions.
* * *
Here is the example
try:
from setuptools import setup, find_packages
except ImportError:
from distribute_setup import use_setuptools
use_setuptools()
from setuptools import setup, find_packages
setup(
# ... other stuff
py_modules=['distribute_setup'],
packages=find_packages(),
package_data={'': ['*.png']}, # for me to include anything with png
install_requires=['numpy', 'treenode', 'investigators'],
tests_require=['mock', 'numpy', 'treenode', 'investigators'],
)
|
Python match a string with regex
Question: I need a python regular expression to check if a word is present in a string.
The string is separated by commas, potentially.
So for example,
line = 'This,is,a,sample,string'
I want to search based on "sample", this would return true. I am crappy with
reg ex, so when I looked at the python docs, I saw something like
import re
re.match(r'sample', line)
But I don't know why there was an 'r' before the text to be matched. Can
someone help me with the regular expression?
Answer: Are you sure you need a regex? It seems that you only need to know if a word
is present in a string, so you can do:
>>> line = 'This,is,a,sample,string'
>>> "sample" in line
True
|
Using python ctypes invoke gtk_builder
Question: my python code is:
gtk = CDLL('/usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so')
builder = gtk.gtk_builder_new()
print gtk.gtk_builder_add_from_file(builder, './mainui.glade', None)
I tested the c code, it works. But with python ctype, the result of
gtk_builder_add_from_file is always 0, e.g there is an error. I'm very
confused..
Answer: Why don't you use the introspection feature? There is a reason it exists.
from gi.repository import Gtk as gtk
class Foo (object):
def __init__(self):
self.builder = gtk.Builder()
self.builder.add_from_file("someui.glade")
self.builder.connect_signals(self)
def run(self, *args):
self.builder.get_object("mainwindow").show()
gtk.main()
def quit(self, *args):
gtk.main_quit()
Foo().run()
* * *
if that is not an option, pass a `GError **` instead of none to get some more
information regarding the issue (might be in your `*.glade` file or missing
permissions)
|
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