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Rock, Paper, Scissor, Spock, Lizard in python, Player 2 automatically wins
Question: for an exercise we need to recreate the game played by the members of the
bigbang theory: Rock, Paper, Scissor, Spock, Lizard. I managed to recreate it
almost completely, the only problem is: Player 2 automatically wins. Can
someone tell me where I need to change the code and also explain why?
import sys
t = len(sys.argv)
if(t < 2 or t > 3):
print("Usage: rpsls.py symbool1 symbool2")
exit()
i = 1
while (i > 0):
a = sys.argv[1]
b = sys.argv[2]
a = a.lower()
b = b.lower()
if(a != "rock" and a != "paper" and a != "scissor" and a != "lizard" and a != "spock"):
print("What's that? please use a real symbol!")
elif(b != "rock" and b != "paper" and b != "scissor" and b != "lizard" and b != "spock"):
print("What's that? please use a real symbol!")
else:
if (a == "paper" and b == "scissor"):
s = True
i = 0
else:
s = False
i = 0
if(a == "paper" and b == "rock"):
s = True
i = 0
else:
s = False
i = 0
if(a == "rock" and b == "lizard"):
s = True
i = 0
else:
s = False
i = 0
if(a == "lizard" and b == "spock"):
s = True
i = 0
else:
s = False
i = 0
if(a == "spock" and b == "scissors"):
s = True
i = 0
else:
s = False
i = 0
if(a == "scissor" and b == "lizard"):
s = True
i = 0
else:
s = False
i = 0
if(a == "lizard" and b == "paper"):
s = True
i = 0
else:
s = False
i = 0
if(a == "paper" and b == "spock"):
s = True
i = 0
else:
s = False
i = 0
if(a == "spock" and b == "rock"):
s = True
i = 0
else:
s = False
i = 0
if(a == "rock" and b == "scissor"):
s = True
i = 0
else:
s = False
i = 0
if(a == b):
print("It's a tie!")
i = 0
exit()
if(s == True):
print("Player 1 wins!")
if(s == False):
print("Player 2 wins!")
Answer: Each of your if statements has an else. Only one of the if statements can be
true, so that means that all the other else statements are evaluated. The
result of that is that the last else statement - which sets s to False - will
"win", so player 2 wins.
You should drop all your else statements, and restructure your code as a
series of `if...elif...` blocks:
if a == "paper" and b == "scissor":
s = True
i = 0
elif a == "paper" and b == "rock":
(Note, if conditions don't need parentheses.)
|
Linking library in python
Question: I want to use the Cantera library in python. I have been using it for C++ and
I am linking my adding these couple lines to my makefile:
CANT_LIB = $HOME/usr/local/Cantera201/lib/
CANT_INC = $HOME/usr/local/Cantera201/include/ -I $HOME/usr/local/Cantera201/include/cantera \
with `CANT_LIB` and `CANT_INC` being called when compiling.
I have very limited experience with python. Is there an equivalent to linking
libraries in python? I have tried adding the cantera path to `PYTHONPATH` but
it did not work. I am working on a Linux server on which I do not have access
to super user and `python 2.6.6`.
Answer: You need to install Cantera's Python module to use it, the raw C/C++ libraries
aren't enough. If you install using [the directions on their
website](http://www.cantera.org/docs/sphinx/html/install.html) it should be
installed to the appropriate Python `site-packages` directory automatically,
and [available for use with just `import
cantera`](http://www.cantera.org/docs/sphinx/html/cython/migrating.html#importing-
the-python-module).
|
Broke Python on Mac by uninstalling Python wrong, how to get Modules to work again?
Question: I'm trying to use Python with the Twisted framework, and have been struggling
to get it running.
I've got some dirt simple python code:
from twisted.internet import reactor
reactor.run()
Buy when I run `python server.py` I get back:
>
> File "server.py", line 1, in <module>
> from twisted.internet import reactor File
> "/Library/Python/2.7/site-packages/twisted/__init__.py", line 53, in
> <module>
> _checkRequirements() File "/Library/Python/2.7/site-
> packages/twisted/__init__.py", line 37, in
> _checkRequirements
> raise ImportError(required + ": no module named zope.interface.")
> ImportError: Twisted requires zope.interface 3.6.0 or later: no module
> named zope.interface.
>
My first assumption was to run `pip install zope.interface`
Unfortunately, all I get from this is:
>
> Requirement already satisfied (use --upgrade to upgrade):
> zope.interface in
>
> /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
> Requirement already satisfied (use --upgrade to upgrade): setuptools
> in
>
> /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
> (from zope.interface)
>
I also tried `easy_install zope.interface`
But that yields similar results:
>
> Searching for zope.interface
> Best match: zope.interface 4.1.1
> zope.interface 4.1.1 is already the active version in easy-install.pth
>
> Using
> /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
> Processing dependencies for zope.interface
> Finished processing dependencies for zope.interface
>
Since apparently zope is installed on my machine, I'm thinking that the
problem could possibly be with the python I've got installed. I installed
Python3 with brew earlier this year, and I think I may have messed up the
python configuration. Any ideas?
**Update** The default python that is on mac should work for everything I was
trying to do above, I verified this on another mac computer. The problem I was
having was that I had corrupted my default python image that came with my mac.
By following the post below I was able to create working virtualenv again for
my python.
Answer: You should do all of your Python work in a
[virtualenv](https://virtualenv.readthedocs.org/en/latest/). If you were to
make a fresh virtualenv for your Twisted development, and always activate it
before working on it, you would have much tighter control over what gets
installed and it would be a lot easier to diagnose problems. So please make a
new virtualenv and `pip install twisted` in it, and then this problem should
go away.
|
Finding the mode of a list using ONLY loops and creating lists in python
Question: I have been trying to figure out how to find the mode of a list **WITHOUT**
using sorting functions nor importing any modules for quite awhile now...
Here's what I have so far:
d = {}
def mode():
for i in mode:
if i in d:
d[i] += 1
else:
d[i] = 1
return
How do I find the output such as the following:
print(mode([1, 5, 6, 1, 1, 2]))
[1]
print(mode([5, 6, 7, 8, 9]))
[5, 6, 7, 8, 9]
Thanks a bunch!
Answer: You need to count the occurrences in your dict and extract the `max` based on
the value returning the list itself if there is no mode.
def mode(l):
d= {}
for i in l:
d.setdefault(i, 0)
d[i] += 1
mx = max(d,key=d.get)
return d[mx] if d[mx] > 1 else l
|
BioPython AlignIO ValueError says strings must be same length?
Question: Input fasta-format text file:
<http://www.jcvi.org/cgi-
bin/tigrfams/DownloadFile.cgi?file=/opt/www/www_tmp/tigrfams/fa_alignment_PF00205.txt>
#!/usr/bin/python
from Bio import AlignIO
seq_file = open('/path/to/fa_alignment_PF00205.txt')
alignment = AlignIO.read(seq_file, "fasta")
Error:
ValueError: Sequences must all be the same length
The input sequences shouldn't have to be the same length since on ClustalOmega
you can align sequences of differing lengths.
This also doesn't work...gets the same error:
alignment = AlignIO.parse(seq_file,"fasta")
for record in alignment:
print(record.id)
**Does anybody who is familiar with BioPython know how to get around this to
align sequences from fasta files?**
Answer: Pad the sequence that is too short and write the records to to a temporary
FASTA file. Than your alignments works as expected:
from Bio import AlignIO
from Bio import SeqIO
from Bio import Seq
import os
input_file = '/path/to/fa_alignment_PF00205.txt'
records = SeqIO.parse(input_file, 'fasta')
records = list(records) # make a copy, otherwise our generator
# is exhausted after calculating maxlen
maxlen = max(len(record.seq) for record in records)
# pad sequences so that they all have the same length
for record in records:
if len(record.seq) != maxlen:
sequence = str(record.seq).ljust(maxlen, '.')
record.seq = Seq.Seq(sequence)
assert all(len(record.seq) == maxlen for record in records)
# write to temporary file and do alignment
output_file = '{}_padded.fasta'.format(os.path.splitext(input_file)[0])
with open(output_file, 'w') as f:
SeqIO.write(records, f, 'fasta')
alignment = AlignIO.read(output_file, "fasta")
print alignment
This outputs:
SingleLetterAlphabet() alignment with 104 rows and 275 columns
TKAAIELIADHQ.......LTVLADLLVHRLQ..AVKELEALLA...QAL SP|A2VGF0.1/208-339
LQELASVINQHE...KV..MLFCGHGCR...Y..AVEEVMALAK...EDL SP|A3D4X6.1/190-319
IKKIAQAIEKAK...KP..VICAGGGVINS.N..ASEELLTLSR...KEL SP|A3DID9.1/192-327
IDEAAEAINKAE...RP..VILAGGGVSIA.G..ANKELFEFAT...QLL SP|A3DIY4.1/192-327
IEKAIELINSSQ...RP..FICSGGGVISS.E..ASEELIQFAE...KIL SP|A4XHS0.1/191-326
IKRAVEAIENSQ...RP..VICSGGGVIAS.R..ASDELKILVE...SEI SP|A4XIL5.1/194-328
VRQAARIIMESE...RP..VIYAGGGVRIS.G..AAPELLELSE...RAL SP|A5D4V9.1/192-327
LQALAQRILRAQ...RP..VIITGDEIVKS.D..ALQAAADFAS...LQL SP|A5ECG1.1/192-328
VEKAVELLWSAR...RV..LVISGRGAR...G..AGPELIGLLD...RAM SP|A5EDH4.1/198-324
IQKAARLIETAE...KP..VIIAGHGVNIS.G..ANEELKTLAE...KSL SP|A5FR34.1/193-328
LDALARDLDSAA...RV..TIYAGIGAR...G..AAARVVQLAG...EAL SP|A5FTR0.1/189-317
VADVAALLRAAR...RP..VIVAGGGVIHSG...AEERLATFAA...DAL SP|A5G0X6.1/217-351
IAEAVSALKGAK...RP..IIYTGGGLINS.GPESAELIVQLAK...RAL SP|A5G2E1.1/199-336
LKKAAEIINRAK...RP..LIYAGGGITLA.G..ASAELRALAA...ALL SP|A5GC69.1/192-327
CRDIVGKLLQSH...RP..VVLGGTGVRLS.R..TEQRLLALVE...DVF SP|A5W0I1.1/200-336
LDQAALKLAAAE...RP..MIIAGGGA..L.H..AAEQLAQLSA...AGL SP|A5W220.1/196-326
LQRAADILNTGH...KV..AILVGAGAL...Q..ATEQVIAIAE...RAL SP|A5W364.1/198-328
IRKAAEMLLAAK...RP..VVYSGGGVILG.G..GSEALTEIAK...SEM SP|A5W954.1/196-331
...
LTELQERLANAQ...RP..VVILGGSRWSD.A..AVQQFTRFAE...... SP|Q220C3.1/190-328
|
GAE/P transaction using static method
Question: I'm trying to figure out how to organize app engine code with transactions.
Currently I have a separate python file with all my transaction functions. For
transactions that are closely related to entities, I was wondering if it made
sense to use a `@staticmethod` for the transaction.
Here is a simple example:
class MyEntity(ndb.Model):
n = ndb.IntegerProperty(default=0)
@staticmethod
@ndb.transactional # does the order of the decorators matter?
def increment_n(my_entity_key):
my_entity = my_entity_key.get()
my_entity.n += 1
my_entity.put()
def do_something(self):
MyEntity.increment_n(self.key)
It would be nice to have `increment_n` associated with the entity definition,
but I have never seen anyone do this so I was wondering if this would be a bad
idea.
MY SOLUTION:
Following Brent's answer, I've implemented this:
class MyEntity(ndb.Model):
n = ndb.IntegerProperty(default=0)
@staticmethod
@ndb.transactional
def increment_n_transaction(my_entity_key):
my_entity = my_entity_key.get()
my_entity.increment_n()
def increment_n(self):
self.n += 1
self.put()
This way I can keep entity related code all in one place and I can easily use
the transactional version or not as needed.
Answer: Yes, it makes sense to use a `@staticmethod` in this case, since the function
doesn't use a class or an instance (`self`).
And yes, the order of decorators is important, as noted in @Kekito's later
answer.
|
Time Looping Python
Question: How can I write code to loop in time python? I want this code loop 10 minutes
in python.
msList =[]
msg = str(raw_input('Input Data :'))
msgList.append(msg)
I do not wanna use `crontab` because I want this code looping in my program.
Answer: Use the `sleep` function from the `time` module. This should do what you're
asking:
from time import sleep
msList =[]
while True:
msg = str(raw_input('Input Data :'))
msgList.append(msg)
sleep(600)
|
Insert into MySQl database after reading csv file?
Question: I have a csv file like this:
[email protected], 01-05-2014
[email protected], 01-05-2014
[email protected], 01-05-2014
[email protected], 01-05-2014
I need to read the above csv file and extract domain name and also the count
of emails address by domain name and date as well. All these things I need to
insert into MySQL database but somehow I am stuck how to insert into MySQL
database after iterating the list I got.
Query will be like this:
INSERT INTO domains(domain_name, cnt, date_of_entry) VALUES (%s, %s, %s);
Below is the code
#!/usr/bin/python
import fileinput
import csv
import os
import sys
import MySQLdb
from collections import defaultdict
lst = defaultdict(list)
d_lst = defaultdict(list)
# ======================== Defined Functions ======================
def get_file_path(filename):
currentdirpath = os.getcwd()
# get current working directory path
filepath = os.path.join(currentdirpath, filename)
return filepath
# ===========================================================
def read_CSV(filepath):
domain_list = []
domain_date_list = []
sorted_domain_list_bydate = defaultdict(list)
with open(filepath, 'rb') as csvfile:
reader = csv.reader(csvfile)
for row in reader:
# insert the 1st & 2nd column of the CSV file into a set called input_list
email = row[0].strip().lower()
date = row[1].strip()
domain_date_list.append([date, email[ email.find("@") : ]])
domain_list.append(email[ email.find("@") : ])
for k, v in domain_date_list:
sorted_domain_list_bydate[k].append(v)
# remove duplicates from domain list
domain_list = list(set(domain_list))
return sorted_domain_list_bydate, domain_list
# ===========================================================
def update_DB(lst):
# open a database connection
db = MySQLdb.connect(host="localhost", # your host, usually localhost
user="root", # your username
passwd="abcdef1234", # your password
db="test") # name of the data base
cur = db.cursor()
a = []
for k, v in lst.items():
# now what should I do here?
# this is what I am confuse
db.commit()
db.close()
# ==========================================================
# ======================= main program =======================================
path = get_file_path('emails.csv')
[lst, d_lst] = read_CSV(path) # read the input file
update_DB(lst) # insert data into domains table
I am confuse in `update_DB` method.
Answer: I am not sure why you have such a complicated program for a simple task. Lets
start from the top:
1. You need to first organize your data correctly by domain, date and then count.
import csv
from collections import defuaultdict, Counter
domain_counts = defaultdict(Counter)
with open('somefile.csv') as f:
reader = csv.reader(f)
for row in reader:
domain_counts[row[0].split('@')[1].strip()][row[1]] += 1
2. Next, you need to insert each _row_ correctly in the database:
db = MySQLdb.connect(...)
cur = db.cursor()
q = 'INSERT INTO domains(domain_name, cnt, date_of_entry) VALUES(%s, %s, %s)'
for domain, data in domain_counts.iteritems():
for email_date, email_count in data.iteritems():
cur.execute(q, (domain, email_count, email_date))
db.commit()
* * *
As your dates are not being inserted correctly, try this updated query
instead:
q = """INSERT INTO
domains(domain_name, cnt, date_of_entry)
VALUES(%s, %s, STR_TO_DATE(%s, '%d-%m-%Y'))"""
|
Python connection to Oracle database
Question: I am writing a Python script to fetch and update some data on a remote oracle
database from a Linux server. I would like to know how can I connect to remote
oracle database from the server.
Do I necessarily need to have an oracle client installed on my server or any
connector can be used for the same?
And also if I use `cx_Oracle` module in Python, is there any dependency that
has to be fulfilled for making it work?
Answer: You have to Install Instance_client for cx_oracle driver to interact with
remote oracle server
<http://www.oracle.com/technetwork/database/features/instant-
client/index-097480.html>.
Use SQLAlchemy (Object Relational Mapper) to make the connection and interact
with Oracle Database.
The below code you can refer for oracle DB connection.
> > > from sqlalchemy import create_engine
>>>
>>> from sqlalchemy.orm import sessionmaker
>>>
>>> engine = create_engine('oracle+cx_oracle://test_user:test_user@ORACSG')
>>>
>>> session_factory = sessionmaker(bind=engine, autoflush=False)
>>>
>>> session = session_factory()
>>>
>>> res = session.execute("select * from emp");
>>>
>>> print res.fetchall()
|
Why Response.Cookies is empty?
Question: When I run this python script
import requests
main_page_request = requests.get("http://carkit.kg/")
cookie = main_page_request.cookies.get("csrftoken", "")
I'm getting proper result, but when I run this code at C#:
string url = @"http://carkit.kg";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Debug.Log(response.Cookies["csrftoken"]); // prints "Null"
it says that response.Cookies is empty. What is the problem?
Answer: You have to add a cookie container to the request. Then it returns the cookie:
CookieContainer c = new CookieContainer();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.CookieContainer = c;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Console.WriteLine(response.Cookies["csrftoken"]);
// prints "csrftoken=E1iRIi7cQvxvJcnSgOgaEP3XPxTHRUfT"
|
sending data using post in python to php with variable
Question: I have this script and I want to replace the date `2015-05-01` (from and to)
with the current date. I am thinking of using **import datetime** and
something like this (I am new to python):
from StringIO import StringIO
import urllib
import urllib2
url = 'http://fme.discomap.eea.europa.eu/fmedatastreaming/AirQuality/AirQualityUTDExport.fmw'
data = "POSTDATA=FromDate=2015-05-01&ToDate=2015-06-01&Countrycode=&InsertedSinceDate=&UpdatedSinceDate=&Pollutant=PM10&Namespace=&Format=XML&UserToken= "
req = urllib2.Request(url, data)
response = urllib2.urlopen(req)
the_page = response.read()
print the_page
**New script**
from StringIO import StringIO
import urllib
import urllib2
import datetime
i = datetime.datetime.now() // gets the date
url = 'http://fme.discomap.eea.europa.eu/fmedatastreaming/AirQuality/AirQualityUTDExport.fmw'
data = "POSTDATA=FromDate="i&ToDate="i"&Countrycode=&InsertedSinceDate=&UpdatedSinceDate=&Pollutant=PM10&Namespace=&Format=XML&UserToken=" //i replaced the fixed date with the variable i
req = urllib2.Request(url, data)
response = urllib2.urlopen(req)
the_page = response.read()
print the_page
Answer: I don't mean to sound harsh, but being new to a language is no excuse for not
learning the language's syntax (quite on the contrary). This line:
data = "POSTDATA=FromDate="i&ToDate="i"&Countrycode=&InsertedSinceDate=&UpdatedSinceDate=&Pollutant=PM10&Namespace=&Format=XML&UserToken="
is obviously broken and raises a SyntaxError:
bruno@bigb:~/Work/playground$ python
Python 2.7.3 (default, Jun 22 2015, 19:33:41)
>>> data = "POSTDATA=FromDate="i&ToDate="i"&Countrycode=&InsertedSinceDate=&UpdatedSinceDate=&Pollutant=PM10&Namespace=&Format=XML&UserToken="
File "<stdin>", line 1
data = "POSTDATA=FromDate="i&ToDate="i"&Countrycode=&InsertedSinceDate=&UpdatedSinceDate=&Pollutant=PM10&Namespace=&Format=XML&UserToken="
^
SyntaxError: invalid syntax
>>>
In this statement the rhs expression actually begins with :
* `"POSTDATA=FromDate="` which is a legal literal string
* `i&ToDate` which is parsed as "`i`" (identifier) "`&`" (operator) "`ToDate`" (identifier)
The mere juxtaposition of a literal string and an identifier (without an
operator) is actually illegal:
bruno@bigb:~/Work/playground$ python
Python 2.7.3 (default, Jun 22 2015, 19:33:41)
>>> i = 42
>>> "foo" i
File "<stdin>", line 1
"foo" i
^
SyntaxError: invalid syntax
>>>
Obviously what you want here is string concatenation, which is expressed by
the `add` ("`+`") operator, so it should read:
"POSTDATA=FromDate=" + i
Then since "&ToDate" is supposed to be a string literal instead of an operator
and a variable you'd have to quote it:
"POSTDATA=FromDate=" + i + "&ToDate="
Then concatenate the current date again:
"POSTDATA=FromDate=" + i + "&ToDate=" + i + "etc..."
Now in your code `i` (not how I would have named a date BTW but anyway) is a
`datetime` object, not a string, so now you'll get a `TypeError` because you
cannot concatenate a string with anything else than a string (hopefully - it
wouldn't make any sense).
FWIW what you want here is not a `datetime` object but the textual ("string")
representation of the date in the "YYYY-MM-DD" format. You can get this from
the `datetime` object using it's `strftime()` method:
today = datetime.datetime.now().strftime("%Y-%m-%d)
Now you have a string that you can concatenate:
data = "POSTDATA=FromDate=" + today + "&ToDate=" + today + "etc..."
This being said:
* this kind of operation is usually done using [string formatting](https://docs.python.org/2/library/string.html#string-formatting)
* and as Ekrem Dogan mentionned, the simplest solution here is to use a higher-level package that will take care of all the boring details of HTTP requests - `requests` being the de facto standard.
|
Killing a Python program using ctrl C
Question: I have an assignment in school which i can't get around and i'm stuck with.
the assignment is to build a program that infinitly spews out random numbers
in a EasyGUI messagebox ( Yeah i know EasyGUI is old xD )
this is my source code:
import easygui
while True:
easygui.msgbox(random.randint(-100, 100))
The problem is that when i run this i can't get out of it. I should be allowed
to use ctrl+C but that doesn't work. Am i missing something?
Thank you in advance!
Answer: using signalhandlers does not seem to be a trivial task when it comes to
easygui, if you can work with quitting when `x` is pressed you can do the
following:
while True:
e = easygui.msgbox(random.randint(-100, 100))
if e is None:
break
`e` will either be a string `"OK"` if you press ok or None if `x` is pressed
so it is probably the simplest way to quit and end the loop.
|
Unable to run python script from shell but able to run it from eclipse(PyDev)
Question: Python version:2.7 OS: CentOS
I have a python project with multiple files spread across different
directories. I am able to run this through Eclipse(PyDev). However I am unable
to run it from linux shell.
The directory structure looks like this:
Projectrepo
|
|
__|__
src conf
| |
| |
buildexec.py |
|
script_variables, list_of_scripts
`buildexec.py` is my main script. `script_variables` and `list_of_scripts` are
two modules which I am referencing from buildexec.py.
I have included `from conf.script_variables import *` in my main script and it
is working fine when I run it on eclipse. But, when I try to run it on shell,
I get an error
`'Traceback (most recent call last): File "buildexec.py", line 6, in <module>
from conf.script_variables import * ImportError: No module named
conf.script_variables'`
I have added PYTHONPATH=/usr/bin/python2.7 and have exported it..
Also, in the main script, I have added
`sys.path.append('/home/tejas/Projectrepo/conf')` before importing the
modules.
Answer: Was a simple solution! My pythonpath was pointing to the default directory
/usr/bin/python2.7. I added the location of the user defined modules also in
the python path using `export
PYTHONPATH=/usr/bin/python2.7:/home/tejas/Projectrepo/conf`
|
write chinese words in csv file using python2.7
Question: I am trying to write Chinese words like 花花公子昊天鞋类专营店 in a CSV file in python,
but not able to do it. I tried solution given here("[issues with writing
Chinese to csv file in
Python](http://stackoverflow.com/questions/29442448/issues-with-writing-
chinese-to-csv-file-in-python)"). Any help will be appreciated.
Answer: The module `unicodecsv` helps with that (you can install that with **pip**):
import unicodecsv
w = unicodecsv.writer(open("test.csv", "w"))
w.writerow((u"花花公子昊天鞋类专营店", 78.10))
del w
The resulting csv file opens succesfully in OpenOffice.
You can also read it back in Python:
r = unicodecsv.reader(open("test.csv", "rb"))
for row in r:
print row[0], row[1]
And when run, it should print:
(user@motoom) ~/Prj/python $ python chinesecsv.py
花花公子昊天鞋类专营店 78.1
|
Parse lines into individual segments - python
Question: I'm new to python and having issues working with a text file. The text file
structure being used is shown. What I'm trying to do is first split the two
polylines into their own variable and then split each variable into individual
coordinates. The end goal is to have it structured as:
polyline 1:
[###, ###] [###, ###]
polyline 2:
[###, ###] [###, ###]
Text file structure:
Polyline;
1: ###,###; ###,###
2: ###,###; ###,###; ###,###
The code I've tried is just working with a single line. While I've been able
to split the single line, I have not been able to move to the next step which
is to split the line further.
f=open('txt.txt', 'r')
pl = []
for line in f.read().split('\n'):
if (line.find('1: ') !=-1):
ln = line.split('1: ')
print ln
f.close()
What is the best way to split the line to the end state?
Answer: First of all you can use `with ... as` statement to open a file which will
close the file at the end of block , secondly you don't have to read the file
and split with `\n` just use a for loop to loop over your file object.
Also for checking the start with digit number you can us regex and in this
case you can use `re.match` function, then you can split the line with `;` and
using a list comprehension split another parts with `,` :
import re
with open('txt.txt') as f:
for line in f:
if re.match(r'\d:.*',line):
ln = [var.split(',') for var in line.split(';')]
print ln
|
Mongodb lack of precision incrementing floats
Question: I have a problem because Mongodb doesn't seem to maintain precision when
incrementing floats. For example, the following should yield `2.0`:
from decimal import Decimal # for python precision
for i in range(40):
db.test.update({}, {'$inc': {'count': float(Decimal(1) / 20)}}, upsert=True)
print db.test.find_one()['count']
2.000000000000001
How can I get around this issue?
Answer: Unfortunately, you can't -- at least not directly. Mongo stores floating-point
numbers as double-precision IEEE floats
(<https://en.wikipedia.org/wiki/IEEE_floating_point>), and those rounding
errors are inherent to the format.
I'm noticing you're using Decimals in your code -- they're converted to Python
floats (which are doubles) before being sent to the DB. If you want to keep
your true decimal precision, you'll have to store your numbers as stringified
Decimals, which means you'll also have to give up Mongo's number-handling
facilities such as `$inc`.
It is, sadly, a tradeoff you'll be confronted to in most databases and
programming languages: IEEE floating-point numbers is the format CPUs natively
deal with, and any attempts to stray away from them (to use arbitrary-
precision decimals like `decimal.Decimal`) come with a big performance and
usability penalty.
|
how to fetch all the documents of the mongodb collection in python
Question: I want to fetch all the documents of the some collection of MongoDB and print
certain attributes within each document. But I am unable to do so.
My code:
import csv
from pymongo import MongoClient
db_client = MongoClient()
db = db_client.pg_new_sw_cur
db_collection_users = db.pg_new_sw
#with open("pg_details_new.csv",'w') as f:
for post in db_collection_users.find():
print post['user_name']
print "==========================="
It is printing nothing on the screen after running it when the collection
consists of thousands of objects/documents when viewed using robomongo.
I am new to MongoDB. So, please help me.
Answer: It would be a wild guess, but I suspect that you have specified an incorrect
collection name:
db_collection_users = db.pg_new_sw
Recheck that `pg_new_sw` actually exists in your local `MongoDB` server
instance and contains documents inside.
|
Unique Template Class without __LINE__ or __COUNTER__ Macros
Question: First, let me start with what I'm trying to do. I'm working on a library that
makes embedding a Python interpreter in C++ code a bit easier, and I'd like to
leverage some C++11 features. I'm using std::functions quite heavily, which is
a problem since Python makes heavy use of classic function pointers.
I've been using fredbaba's solution found at
<http://stackoverflow.com/a/18422878>
which may not be a good idea, but the reasoning seems sound; for every
std::function you'd like a pointer too, you need to create some class or
struct with a static function that invokes the std::function of interest, and
any class function pointers can point to the static function.
However, that means you've got to ensure every struct created is unique; the
poster from that thread uses a unique integer as an identifier, which is
cumbersome. In my code I use the LINE macro (COUNTER never seems to work), but
that of courses forces me to put everything in one file to avoid line number
conflicts.
I've found similar questions asked but none of them really do it; in order for
this to work the identifier has to be a compile time constant, and many of the
solutions I've found fail in this regard.
Is this possible? Can I cheat the system and get pointers to my
std::functions? If you're wondering why I need to... I take a std::function
that wraps some C++ function, capture it in yet another function, then store
that in a std::list. Then I create a function pointer to each list element and
put them in a Python Module I create.
// Store these where references are safe
using PyFunc = std::function<PyObject *(PyObject *, PyObject *)>;
std::list<PyFunc> lst_ExposedFuncs;
...
// Expose some R fn(Args...){ ... return R(); }
template <size_t idx, typename R, typename ... Args>
static void Register_Function(std::string methodName, std::function<R(Args...)> fn, std::string docs = "")
{
// Capture the function you'd like to expose in a PyFunc
PyFunc pFn = [fn](PyObject * s, PyObject * a)
{
// Convert the arguments to a std::tuple
std::tuple<Args...> tup;
convert(a, tup);
// Invoke the function with a tuple
R rVal = call<R>(fn, tup);
// Convert rVal to some PyObject and return
return alloc_pyobject(rVal);
};
// Use the unique idx here, where I'll need the function pointer
lst_ExposedFunctions.push_back(pFn);
PyCFunction fnPtr = get_fn_ptr<idx>(lst_ExposedFunctions.back());
}
From there on I actually do something with fnPtr, but it's not important.
Is this crazy? Can I even capture a function like that?
John
Answer: I do something vaguely similar for a similar use case (actually a class
factory for use with a JNI). My technique is to use a `template struct` on an
`unsigned` with a specialisation for 0: Each `struct` contains a function -
you could adapt this to a `static` member for which a pointer would be valid.
I also show how you could call a function `foo` with a parameter dependent on
a particular specialisation (not sure you need this, but included just in
case).
extern bar* foo(const unsigned& id); // The function that gets called
template<unsigned N> struct Registrar
{
static bar* func()
{
return foo(N - 1);
}
private:
Registrar<N - 1> m_next; // Instantiate the next one.
};
template<> struct Registrar<0> // To block the recursion
{
};
namespace
{
Registrar</*ToDo - total number here*/> TheRegistrar;
}
`TheRegistrar` is pretty much a metasyntactic variable which ensures that a
given number of specialisations, and hence `static` functions are created.
(For various technical reasons I have to instantiate my templates in reverse
order: if you don't need that then you can adjust accordingly.)
I imagine it's the interplay between `func` and `foo` that you'll need to
adapt to your needs. Each `N`, of course, is that _compile-time_ constant that
you seek.
|
Python - Control window with pywinauto while the window is minimized or hidden
Question: **What I'm trying to do:**
I'm trying to create a script in python with pywinauto to automatically
install notepad++ in the background (hidden or minimized), notepad++ is just
an example since I will edit it to work with other software.
**Problem:**
The problem is that I want to do it while the installer is hidden or
minimized, but if I move my mouse the script will stop working.
**Question:**
How can I execute this script and make it work, while the notepad++ installer
is hidden or minimized.
**This is my code so far** :
import sys, os, pywinauto
pwa_app = pywinauto.application.Application()
app = pywinauto.Application().Start(r'npp.6.8.3.Installer.exe')
Wizard = app['Installer Language']
Wizard.NextButton.Click()
Wizard = app['Notepad++ v6.8.3 Setup']
Wizard.Wait('visible')
Wizard['Welcome to the Notepad++ v6.8.3 Setup'].Wait('ready')
Wizard.NextButton.Click()
Wizard['License Agreement'].Wait('ready')
Wizard['I &Agree'].Click()
Wizard['Choose Install Location'].Wait('ready')
Wizard.Button2.Click()
Wizard['Choose Components'].Wait('ready')
Wizard.Button2.Click()
Wizard['Create Shortcut on Desktop'].Wait('enabled').CheckByClick()
Wizard.Install.Click()
Wizard['Completing the Notepad++ v6.8.3 Setup'].Wait('ready', timeout=30)
Wizard['CheckBox'].Wait('enabled').Click()
Wizard.Finish.Click()
Wizard.WaitNot('visible')
Answer: The problem is here:
Wizard['Create Shortcut on Desktop'].Wait('enabled').CheckByClick()
`CheckByClick()` uses `ClickInput()` method that moves real mouse cursor and
performs a realistic click.
Use `Check()` method instead.
[EDIT] If the installer doesn't handle BM_SETCHECK properly the workaround may
look so:
checkbox = Wizard['Create Shortcut on Desktop'].Wait('enabled')
if checkbox.GetCheckState() != pywinauto.win32defines.BST_CHECKED:
checkbox.Click()
I will fix it in the next pywinauto release by creating methods `CheckByClick`
and `CheckByClickInput` respectively.
* * *
[EDIT 2] I tried your script with my fix and it works perfectly (and very
fast) with and without mouse moves. Win7 x64, 32-bit Python 2.7, pywinauto
0.5.3, run as administrator.
import sys, os, pywinauto
app = pywinauto.Application().Start(r'npp.6.8.3.Installer.exe')
Wizard = app['Installer Language']
Wizard.Minimize()
Wizard.NextButton.Click()
Wizard = app['Notepad++ v6.8.3 Setup']
Wizard.Wait('visible')
Wizard.Minimize()
Wizard['Welcome to the Notepad++ v6.8.3 Setup'].Wait('ready')
Wizard.NextButton.Click()
Wizard.Minimize()
Wizard['License Agreement'].Wait('ready')
Wizard['I &Agree'].Click()
Wizard.Minimize()
Wizard['Choose Install Location'].Wait('ready')
Wizard.Button2.Click()
Wizard.Minimize()
Wizard['Choose Components'].Wait('ready')
Wizard.Button2.Click()
Wizard.Minimize()
checkbox = Wizard['Create Shortcut on Desktop'].Wait('enabled')
if checkbox.GetCheckState() != pywinauto.win32defines.BST_CHECKED:
checkbox.Click()
Wizard.Install.Click()
Wizard['Completing the Notepad++ v6.8.3 Setup'].Wait('ready', timeout=30)
Wizard.Minimize()
Wizard['CheckBox'].Wait('enabled').Click()
Wizard.Finish.Click()
Wizard.WaitNot('visible')
|
scipy.io.savemat How to save global variables?
Question: I'm trying to use Python like one would do in Matlab. Basically I have some
Python code for which I have run and it has generated some global variables.
Say, a = 5 b = 3
I would like to save these to a .mat file , that will be openable by Matlab.
The goal is to be able to see the global variables in Matlab, just as one
would when saving to a .mat file in Matlab.
I've seen examples where savemat is used to save dictionaries/arrays, but not
where it saves the global variables.
How may I do so? Is this something that scipy just cannot do?
Thanks.
Answer: You most probably don't want to save globals, but locals (though the variables
are local to the interpreter). You can access and update them through the
`locals()` and `globals()` functions.
From there you can use your preferred method of storage, such as
[pickle](https://docs.python.org/3/library/pickle.html),
[marshal](https://docs.python.org/3/library/marshal.html),
[json](https://docs.python.org/3/library/json.html) or others, depending on
which level of security you want and which object types you have at hand.
However, be wary that messing with those functions may get you into some
trouble, since they also report functions and some internal variables.
However, if you intend to (like Matlab) just load and store variables through
the GUI, you may want to check the **[Spyder
IDE](http://pythonhosted.org/spyder/)** ([GitHub
project](https://github.com/spyder-ide/spyder)). It is a very nice IDE, geared
toward scientific usage and very similar (in appearance) to Matlab's old
interface. Most importantly, it offers a tab/pane named "**Variable explorer**
" which tracks what you want to store, and have both a "**Save data as...** "
and "**Import data** " buttons and the "Save data as..." dialog supports
saving to Spyder data files (_.spydata), Matlab files (_.mat) and HDF5 (*.h5).
If you want to do this programatically, you may check how Spyder does it.
|
randint in Python 3.5 doesn't work
Question: I am a new to Python, and I ran into some issues when developing a _D &D Dice_
program.
import random
print("Hi,here you can roll all D´n´D Dice´s!")
dice=input("What dice do u want?D4,D6,D8,D10,D12,D20 or D100?")
if dice=="D4" or "d4":
print(random.randint(1,4))
elif dice=="D6" or "d6":
print(random.randint(1,6))
elif dice=="D8" or "d8":
print(random.randint(1,8))
elif dice=="D10"or"d10":
print(random.randint(1,10))
elif dice=="D12"or"d12":
print(random.randint(1,12))
elif dice=="D20"or"d20":
print(random.randint(1,20))
elif dice=="D100"or"d100":
print(random.randint(1,100))
else: print("No?Ok!")
When I run the program and enter the number of dice, it always enter the first
`if` statement.
Answer: You want to write:
if dice=="D4" or dice=="d4":
instead of:
if dice=="D4" or "d4":
`"d4"` by itself has a (true) boolean value because it isn't an empty string.
|
Select option from dynamic dropdown list using selenium
Question: I am trying to fill out the dropdown menus found on this
[homepage](http://www.tirerack.com/content/tirerack/desktop/en/homepage.html)
using Python and the selenium package. To Select Make I am using the following
code
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.support.select import Select
driver = webdriver.Firefox()
driver.implicitly_wait(5)
driver.get('http://www.tirerack.com/content/tirerack/desktop/en/homepage.html')
button = driver.find_element_by_tag_name('button')
ActionChains(driver).click(button).perform()
select_make = driver.find_element_by_id('vehicle-make')
Select(select_make).select_by_value("BMW")
However this does not seem to actually "Select the BMW" option. I tried to
follow the method explained in
[this](http://sqa.stackexchange.com/questions/1355/what-is-the-correct-way-to-
select-an-option-using-seleniums-python-webdriver) post. Can someone show me
what I am doing wrong?
Answer: From the question you linked to the accepted answer iterates over the options
and finds the matching text.
select_make = driver.find_element_by_id('vehical-make')
for option in select_make.find_elements_by_tag_name('option'):
if option.text == 'BMW':
option.click() # select() in earlier versions of webdriver
break
Running this in Java I got the message that the element is not visible, so I
forced it:
WebDriver driver = new FirefoxDriver();
driver.get("http://www.tirerack.com/content/tirerack/desktop/en/homepage.html");
Thread.sleep(3000);
driver.findElement(By.tagName("button")).click();
WebElement select_make = driver.findElement(By.id("vehicle-make"));
select_make.click();
JavascriptExecutor js = (JavascriptExecutor) driver;
String jsDisplay = "document.getElementById(\"vehicle-make\").style.display=\"block\"";
js.executeScript(jsDisplay, select_make);
for (WebElement option : select_make.findElements(By.tagName("option"))) {
System.out.println(option.getText());
if ("BMW".equals(option.getText())) {
option.click();
break;
}
}
If you add the JavascriptExecutor lines (in python) I think it will work.
|
Python Tkinter: Reading Serial Values
Question: I would like to read serial values into my Tkinter GUI. Either into a text
window or eventually to a text label widget which updates every second or so.
The issue I am having is with the queue class. The error I am getting is:
AttributeError: 'Applcation' object has no attribute 'queue'
Here is my code:
#!/usr/bin/env python
from tkinter import *
from tkinter import messagebox
from time import sleep
import picamera
import os
import serial
import sys
import RPi.GPIO as GPIO
import _thread
import threading
import random
import queue
# Setup GPIO pin(s)
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(18, GPIO.OUT)
GPIO.output(18, False)
#==============================================================
# Declaration of Constants
# none used
#==============================================================
class SerialThread(threading.Thread):
def __init__(self, queue):
threading.Thread.__init__(self)
self.queue = queue.Queue()
def read_sensor_values(self):
ser = serial.Serial('/dev/ttyUSB0', 9600)
while True:
if ser.inWaiting:
text = ser.readline(s.inWaiting)
self.queue.put(text)
self.pressures_txt.insert(0.0,values)
class Application(Frame):
""" GUI Application for taking photos. """
def __init__(self, master):
super(Application, self).__init__(master)
self.grid()
self.create_widgets()
self.setup_camera()
def create_widgets(self):
Checkbutton( self, text = "Read Pressure Values", variable = self.mode2, command = self.process_serial, bg = 'white').grid(row = 4, column = 0, sticky = W+E+N+S)
# create text field to display pressure values from arduino
self.pressures_txt = Text(self, height = 3, wrap = WORD)
self.pressures_txt.grid(row=9, column = 0, columnspan =3)
def process_serial(self):
#self.text.delete(1.0, END)
while self.queue.qsize():
try:
self.text.insert(END, self.queue.get())
self.pressures_txt.insert(0.0, self.queue.get())
except queue.Empty:
pass
self.after('1000', self.process_serial)
#................. end of method: read_sensor_values ................
#=================================================================
# main
#=================================================================
root = Tk() # Create the GUI root object
root.title("Control V1.0")
app = Application(root) # Create the root application window
root.mainloop()
The code I have posted is an abbreviated version of the entire program. I have
removed sections that are supposedly irrelevant. I am running in python3. I
suspect I may have an error in indentation but I am not certain.
I am using the code from the following link for my serial reading class:
<https://www.daniweb.com/programming/software-
development/threads/496499/using-a-checkbutton-to-import-serial-data-into-
python-tkinter>
Answer: The problem is that the `self.queue` in `read_sensor_values` belongs to a
`SerialThread` object. When you say `self.queue` in the `process_serial`
method of your `Application` object, it refers to a non-existent `queue`
attribute of the `Application` object. Perhaps you ought to make the
`SerialThread` object an attribute of your `Application` object. Then
`process_serial` could refer to `self.serial.queue` or whatever you name it.
|
generic scoring module using python pandas
Question: Hi I'm trying to develop a generic scoring module for grading students based
on variety of attributes. I'm trying to develop a generic method using python
pandas Input: An input data frame with student ID and UG Major and attributes
for scoring (I called df_input) An input ref. data frame that contains scoring
params
Process: Based on the variable type, developing a process to calculate scores
for each attribute
Output: Input data frame with added cols that capture the attribute score
Example:
df_input
+
------------+-----------+----+------------+-----+------+
| STUDENT_ID | UG_MAJOR | C1 | C2 | C3 | C4 |
+------------+-----------+----+------------+-----+------+
| 123 | MATH | A | 8000-10000 | 12% | 9000 |
| 234 | ALL_OTHER | B | 1500-2000 | 10% | 1500 |
| 345 | ALL_OTHER | A | 2800-3000 | 8% | 2300 |
| 456 | ALL_OTHER | A | 8000-10000 | 12% | 3200 |
| 980 | ALL_OTHER | C | 1000-2500 | 15% | 2700 |
+------------+-----------+----+------------+-----+------+
df_ref +
---------+---------+---------+
| REF_COL | REF_VAL | REF_SCR |
+---------+---------+---------+
| C1 | A | 10 |
| C1 | B | 20 |
| C1 | C | 30 |
| C1 | NULL | 0 |
| C1 | MISSING | 0 |
| C1 | A | 20 |
| C1 | B | 30 |
| C1 | C | 40 |
| C1 | NULL | 10 |
| C1 | MISSING | 10 |
| C2 | <1000 | 0 |
| C2 | >1000 | 20 |
| C2 | >7000 | 30 |
| C2 | >9500 | 40 |
| C2 | MISSING | 0 |
| C2 | NULL | 0 |
| C3 | <3% | 5 |
| C3 | >3% | 10 |
| C3 | >5% | 100 |
| C3 | >7% | 200 |
| C3 | >10% | 300 |
| C3 | NULL | 0 |
| C3 | MISSING | 0 |
| C4 | <5000 | 10 |
| C4 | >5000 | 20 |
| C4 | >10000 | 30 |
| C4 | >15000 | 40 |
+---------+---------+---------+
+------------+-----------+----+------------+-----+------+--------+--------+--------+---------+
| Req.Output | | | | | | | | | |
+------------+-----------+----+------------+-----+------+--------+--------+--------+---------+
| STUDENT_ID | UG_MAJOR | C1 | C2 | C3 | C4 | C1_SCR | C2_SCR | C3_SCR | TOT_SCR |
| 123 | MATH | A | 8000-10000 | 12% | 9000 | | | | |
| 234 | ALL_OTHER | B | 1500-2000 | 10% | 1500 | | | | |
| 345 | ALL_OTHER | A | 2800-3000 | 8% | 2300 | | | | |
| 456 | ALL_OTHER | A | 8000-10000 | 12% | 3200 | | | | |
| 980 | ALL_OTHER | C | 1000-2500 | 15% | 2700 | | | | |
+------------+-----------+----+------------+-----+------+--------+--------+--------+---------+
I want to see if any thing like a function be developed to accomplish this
Thank you Pari
Answer: If I understand the question correctly, you are trying to store a collection
of rules in `df_ref` that are to be applied to `df_input` to generate scores.
While this certainly can be done, you should make sure that your rules are
well defined. This would also guide you in writing the corresponding scoring
function.
For instance, suppose one of the students gets a value of `10000` in column
`C3`. `10000` is larger than `1000`, `7000` and `9500`. This means that the
score is ambiguous. Suppose you want to choose the highest of all scores from
this particular column. Then, you need another table specifying the choice
rule for each column when multiple scores are selected.
Second, you should think about the type of Python variable stored in 'REF_VAL'
column. If `>7000` is a string, you would have to do extra work to determine
the score. Consider storing this as `7000` instead and specifying comparison
operator elsewhere.
Finally, looking at your current rules, there seems to be a pattern. Each
score is associated with `NULL`, `MISSING` or a range cutoff. This can be
captured as follows:
import pandas as pd
import numpy as np
from itertools import dropwhile
# stores values and scores for special values and cutoff values
sample_range_rule = {
'MISSING' : 0,
'NULL' : 0,
'VALS' : [
(0, 0),
(10, 50),
(70, 75),
(90, 100),
(100, 100)
]
}
# takes a dict with rules and produces a scoring function
def getScoringFunction(range_rule):
def score(val):
if val == 'MISSING':
return range_rule['MISSING']
elif val == 'NULL':
return range_rule['NULL']
else:
return dropwhile(lambda (cutoff, score): cutoff < val,
range_rule['VALS']).next()[1]
return score
sample_scoring_function = getScoringFunction(sample_range_rule)
for test_value in ['MISSING', 'NULL', 0, 12, 55, 66, 99]:
print 'Input', test_value,
print 'Output', sample_scoring_function(test_value)
After you have a dict specifying a rule for every column, you can do the
following:
`df['Ck_SCR'] = df['Ck'].apply(getScoringFunction(Ck_dct))`
Converting pandas DataFrame with two columns to a dict of this form should not
be to difficult.
|
MySQL special chars lost when queried in Python. (But works with Django.)
Question: I have a MySQL database that is utf8 encoded. It contains a row with a value
"sauté". Note the accent over the e.
When I select this data using a Django application then it correctly detects
the é. However, when I execute it as a Python program then this information
(the special e) seems to be lost.
I've tried various combinations of encode and decode and "from **future**
import unicode_literals" and putting a "u" in front of the sauté string and
putting a u in front of the query string. No luck. How can I get this info
correctly out of my database (with Python) and test for it?
# Connection when excute as .py: (Django is usual in settings.py)
cursor = MySQLdb.connect(host='<xxx>',user="<xxx>", passwd="<xxx>", db="<xxx>",
unix_socket = 'path/mysql.sock'
).cursor()
# Same code in Django and Python execution:
cursor.execute(select line from my_table where id = 27)
results = cursor.fetchall()
for r in results:
line = r[0]
if re.search("sauté", line):
do_something() # Should get here, but only with Django
Answer: Thanks to JD Vangsness (in the comments) for the answer.
I needed to add charset='utf8' to the connection parameters.
cursor = MySQLdb.connect(host='<xxx>',user="<xxx>", charset='utf8', passwd="<xxx>", db="<xxx>", unix_socket = 'path/mysql.sock').cursor()
And then I also needed to make the comparison string unicode:
u"sauté"
|
IGNORECASE errors in Python's re.Scanner?
Question: There is hidden but well known
[functionality](http://code.activestate.com/recipes/457664-hidden-scanner-
functionality-in-re-module/) in re module
import re
def s_ident(scanner, token): return token
def s_operator(scanner, token): return "op%s" % token
def s_float(scanner, token): return float(token)
def s_int(scanner, token): return int(token)
scanner = re.Scanner([
(r"[a-zA-Z]\w*", s_ident),
(r"\d+\.\d*", s_float),
(r"\d+", s_int),
(r"=|\+|-|\*|/", s_operator),
(r"\s+", None),
])
print scanner.scan("Sum = 3*foo + 312.50 + bar")
# (['Sum', 'op=', 3, 'op*', 'foo', 'op+', 312.5, 'op+', 'bar'], '')
I want to use IGNORECASE flag here but it seems it does not work:
import re
def s_ident(scanner, token): return token
def s_operator(scanner, token): return "op%s" % token
def s_float(scanner, token): return float(token)
def s_int(scanner, token): return int(token)
scanner = re.Scanner([
(r"(?i)[a-z]\w*", s_ident),
(r"\d+\.\d*", s_float),
(r"\d+", s_int),
(r"=|\+|-|\*|/", s_operator),
(r"\s+", None),
])
print scanner.scan("Sum = 3*foo + 312.50 + bar")
# ([], 'Sum = 3*foo + 312.50 + bar')
Is it a issue of the Scanner or error in my code? Is it possible to implement
non-case-sensitive matching using Scanner?
This issue was initially reproduced on Python 2.7.9.
Expected value: (['Sum', 'op=', 3, 'op*', 'foo', 'op+', 312.5, 'op+', 'bar'],
'')
Actual value: ([], 'Sum = 3*foo + 312.50 + bar')
Answer: You can pass the `flags` parameter to the constructor.
scanner = re.Scanner([
(r"[a-z]\w*", s_ident),
(r"\d+\.\d*", s_float),
(r"\d+", s_int),
(r"=|\+|-|\*|/", s_operator),
(r"\s+", None),
], flags=re.IGNORECASE)
Source for `Scanner`:
<https://github.com/python/cpython/blob/master/Lib/re.py#L345>
|
Django - Autocomplete_Light's "Add Another" popup declares: "'initial' is an invalid keyword argument for this function"
Question: I am working on getting the "add another" popup to work with `django-
autocomplete_light`.
Following along in the docs:
<http://django-autocomplete-light.readthedocs.org/en/latest/addanother.html>
I have set up my URLs:
import autocomplete_light.shortcuts as al
from AlmondKing.FinancialLogs import models
from AlmondKing.FinancialLogs import forms
urlpatterns = [
url(r'^branches/autocreate/$', al.CreateView.as_view(
model=models.CompanyBranch, form_class=forms.CompanyBranch),
name='branch_autocreate'),
]
and my autocomplete_light_registry.py
al.register(CompanyBranch,
search_fields=['^branch_name'],
attrs={
'placeholder': 'Branch',
'data-autocomplete-minimum-characters': 1,
},
widget_attrs={
'data-widget-maximum-values': 1,
'class': 'modern-style',
},
add_another_url_name='company:branch_autocreate',
)
However, when I click the plus sign to add a new related object, I get the
following error:
> TypeError at /company/branches/autocreate/
>
> 'initial' is an invalid keyword argument for this function
I've been trying to find a way to do this for a while and I'm so close!
Now, I am hoping someone can read the traceback and help me understand what
went wrong:
Environment:
Request Method: GET
Request URL: http://localhost:8000/company/branches/autocreate/?_popup=1&winName=id_branch
Django Version: 1.8.2
Python Version: 3.4.3
Installed Applications:
('django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'AlmondKing.InventoryLogs',
'AlmondKing.FinancialLogs',
'AlmondKing.AKGenius',
'autocomplete_light')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'django.middleware.security.SecurityMiddleware',
'AlmondKing.AKGenius.middleware.RequireLoginMiddleware')
Traceback:
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\core\handlers\base.py" in get_response
132. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\views\generic\base.py" in view
71. return self.dispatch(request, *args, **kwargs)
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\views\generic\base.py" in dispatch
89. return handler(request, *args, **kwargs)
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\views\generic\edit.py" in get
245. return super(BaseCreateView, self).get(request, *args, **kwargs)
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\views\generic\edit.py" in get
205. form = self.get_form()
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\views\generic\edit.py" in get_form
74. return form_class(**self.get_form_kwargs())
File "C:\Users\Adam\Envs\AlmondKing\lib\site-packages\django\db\models\base.py" in __init__
480. raise TypeError("'%s' is an invalid keyword argument for this function" % list(kwargs)[0])
Exception Type: TypeError at /company/branches/autocreate/
Exception Value: 'initial' is an invalid keyword argument for this function
Answer: Try this:
add_another_url_name='company:branch_autocreate',
add_another_url_name='branch_autocreate',
|
Python File handling: standard input and output
Question:
import sys
fileobject=open('file.txt','w')
fileobject.write(sys.stdin.readline())
Cat
In the above code, shouldn't cat be in file after execution? However, when I
run it, I find file empty. If my code is wrong, can someone explain how
`sys.stdin.read()` and `sys.stdout.write()` work and their uses?
Answer: You need to close the file
import sys
fileobject = open('file.txt', 'w')
fileobject.write(sys.stdin.readline())
Cat
fileobject.close()
If you want to see the updated file content before closing the file or exiting
the program you can use flush():
fileobject.flush()
Check this [StackOverflow
Question](http://stackoverflow.com/questions/14555402/understanding-stdin-
stdout-stderr%20question) for standard input/output
|
DHT Sensor Python script error
Question: I have a sensor type DHT22 connected to a raspberry. I have written a script
in python but when I run it I get errors
#!/usr/bin/python
import MySQLdb
import subprocess
import re
import sys
import time
import datetime
import Adafruit_DHT
conn = MySQLdb.connect("localhost","zeus","gee3g673r","logi")
while(True):
date = time.strftime("%d/%m/%Y")
clock = time.strftime("%H:%M")
#output = subprocess.check_output(["/usr/bin/AdafruitDHT.py 2302", "4"]);
output = Adafruit_DHT.read_retry(Adafruit_DHT.AM2302, 4)
matches = re.search("Temp =\s+([0-9.]+)", output)
if (not matches):
time.sleep(0)
continue
temp = float(matches.group(1))
matches = re.search("Hum =\s+([0-9.]+)", output)
if (not matches):
time.sleep(0)
continue
humidity = float(matches.group(1))
# MYSQL DATA Processing
c = conn.cursor()
c.execute("INSERT INTO data_th (date, clock, temp, hum) VALUES (%s, %s,%s, %s)",(date, clock, temp, humidity))
#print "DB Loaded"
time.sleep(360)
This is the error encountered on running the script:
root@raspberrypi:/home# ./hdt.py
Traceback (most recent call last):
File "./dht.py", line 22, in <module>
matches = re.search("Temp =\s+([0-9.]+)", output)
File "/usr/lib/python2.7/re.py", line 142, in search
return _compile(pattern, flags).search(string)
TypeError: expected string or buffer
Answer: Adafruit_DHT.read_retry() does not return string. re.search expects string as
second parameter.
Please have a look at code below (taken from
[Adafruit_Python_DHT/examples](https://github.com/adafruit/Adafruit_Python_DHT/blob/master/examples/AdafruitDHT.py)):
# Try to grab a sensor reading. Use the read_retry method which will retry up
# to 15 times to get a sensor reading (waiting 2 seconds between each retry).
humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
# Un-comment the line below to convert the temperature to Fahrenheit.
# temperature = temperature * 9/5.0 + 32
# Note that sometimes you won't get a reading and
# the results will be null (because Linux can't
# guarantee the timing of calls to read the sensor).
# If this happens try again!
if humidity is not None and temperature is not None:
print 'Temp={0:0.1f}* Humidity={1:0.1f}%'.format(temperature, humidity)
else:
print 'Failed to get reading. Try again!'
sys.exit(1)
|
a "Pygame error", not able to open .wav file
Question: I have a problem with my Pygame program. I need help. The wav file is in the
same directory as the python file. I run It in terminal- Python3:
import pygame.mixer
sounds = pygame.mixer
sounds.init()
def wait_finish(channel):
while channel.get_busy():
pass
asked = 0
true = 0
false = 0
choice = str(input("Push 1 for true, 2 for false, 0 to end"))
while choice != '0':
if choice == '1':
asked = asked + 1
true = true + 1
s = sounds.Sound("correct.wav")
wait_finish(s.play())
if choice == '2':
asked = asked + 1
false = false + 1
s = sounds.Sound("wrong.wav")
wait_finish(s.play())
choice = str(input("Push 1 for true, 2 for false, 0 to end"))
print ("you asked" +str(asked) + "questions")
print ("there were" +str(false) + "wrong answers")
print ("and" + str(true) + "correct answers")
...it throws- pygame.error: Unable to open file 'correct.wav'
Answer: Rather than have a discussion in the comments section I'll post this.
Once `def wait_finish(channnel):` has been altered to `def
wait_finish(channel):` and the issue with `sounds.Sound` rather than
`sounds.Sounds` has been resolved, the program works fine with normal .wav
files on my machine.
I am convinced that the error of Sound or Sounds for calling the wrong.wav
file to be played would explain the "unable to open file wrong.wav" message.
If pygame doesn't like something about the file it may well not play it and
this is where a line like:
sounds.pre_init(frequency=22050, size=-16, channels=2, buffer=4096)
(called before `sounds.init()`) might come into play.
(NB you might have to use a different buffer option as I am testing with
pygame for python 2.7)
On my box, if pygame doesn't like or cannot find the file, I get no error at
all but the speakers click when the call to play is made.
All I can suggest at this point is that you try an entirely different wav file
to the current one you are using for wrong answers and see if it makes a
difference. Just for the record, I changed your wait_finish function to :
def wait_finish(channel):
while channel.get_busy():
pygame.time.Clock().tick(10)
|
Merging tables from two different databases (Python)
Question: I have two databases `Database1.db` and `Database2.db`. The databases contain
tables with **matching names and matching columns** (and the Primary key is
the 'Date' column in both). The only difference between the two is that the
entries in Database1 are from 2013 and the entries in Database2 are from 2014.
I would like to merge these two databases so that all the 2013 and 2014 data
ends up **in one table** in a third database (let's call it Database3.db).
To be clear, here is what the databases I'm working with currently contain and
what I want the third resulting database to contain:
Database1.db:
Table Name: GERMANY_BERLIN
Date Morning Day Evening Night
01.01.2013 0.5 0.2 0.2 0.1
02.01.2013 0.4 0.3 0.1 0.2
...
Database2.db:
Table Name: GERMANY_BERLIN
Date Morning Day Evening Night
01.01.2014 0.6 0.2 0.1 0.1
02.01.2014 0.5 0.2 0.3 0.0
...
I would like to have create a resulting Database3 with the following data:
Database2.db:
Table Name: GERMANY_BERLIN
Date Morning Day Evening Night
01.01.2013 0.5 0.2 0.2 0.1
02.01.2013 0.4 0.3 0.1 0.2
01.01.2014 0.6 0.2 0.1 0.1
02.01.2014 0.5 0.2 0.3 0.0
...
I haven't been able to find anything directly helpful on this online yet
(perhaps JOINS could be used somehow?
bhttp://www.tutorialspoint.com/sqlite/sqlite_using_joins.htm) so any
suggestions would be greatly appreciated!
PS. SQLite has been used to create the existing databases and is the database-
related Python library that I'm most familiar with
Answer: You can easly export a .db into a csv ([How to export sqlite to CSV in Python
without being formatted as a
list?](http://stackoverflow.com/questions/10522830/how-to-export-sqlite-to-
csv-in-python-without-being-formatted-as-a-list)) and import it again into .db
([Importing a CSV file into a sqlite3 database table using
Python](http://stackoverflow.com/questions/2887878/importing-a-csv-file-into-
a-sqlite3-database-table-using-python)) for the step 1 just append the result
to the same cvs file.
|
Python 3 CSV not writing
Question: When I open my csv file I see nothing. Is this the right way to build a csv
file? Just trying to learn it all. Thanks for all your help.
import csv
from urllib.request import urlopen
from bs4 import BeautifulSoup
html = urlopen("http://shop.nordstrom.com/c/designer-handbags?dept=8000001&origin=topnav#category=b60133547&type=category&color=&price=&brand=&stores=&instoreavailability=false&lastfilter=&sizeFinderId=0&resultsmode=&segmentId=0&page=1&partial=1&pagesize=100&contextualsortcategoryid=0")
nordHandbags = BeautifulSoup(html)
bagList = nordHandbags.findAll("a", {"class":"title"})
f = csv.writer(open("./nordstrom.csv", "w"))
f.writerow(["Product Title"])
for title in bagList:
productTitles = title.contents[0]
f.writerow([productTitles])
Answer: Really hard to see how you could fail to have at least a `"Product Title"`
header in that file. Are you checking the file _after_ you have tgerminated
the Python interpreter? This, because there is no explicit close of the file
in that code, and until it is closed, its contents may be cached in memory.
More Pythonic, and avoiding this problem, is
with open("./nordstrom.csv", "w") as csvfile:
f = csv.writer( csvfile)
f.writerow(["Product Title"])
# etc.
pass # close the with block, csvfile is now closed.
Also (grasping at straws) are you opening the file with a text editor to check
it, or just using the `type` command in Windows cmd.exe? Because, if the file
doesn't contain an explicit LF, the `C:\wherever\ >`prompt may overwrite the
header before you see it.
|
How to authenticate in django app via C#?
Question: I have a python script:
import requests
main_page_request = requests.get("http://carkit.kg/")
csrf_cookie = main_page_request.cookies.get("csrftoken", "")
r = requests.post("http://carkit.kg/", data={u'username': u'admin', u'password': u'admin', 'csrfmiddlewaretoken': csrf_cookie }, cookies={'csrftoken': csrf_cookie})
print r.url
carkit.kg/ - is a login url in django app. Script prints one url if
authentication succeed and another in other case. I tried to rewrite this
script in C# (Unity3D game):
//get token
string url = "http://carkit.kg";
HttpWebRequest tokenRequest = (HttpWebRequest)WebRequest.Create(url);
tokenRequest.CookieContainer = new CookieContainer();
HttpWebResponse tokenResponse = (HttpWebResponse)tokenRequest.GetResponse();
String token = tokenResponse.Cookies["csrftoken"].ToString().Split('=')[1];
//login
HttpWebRequest loginRequest = (HttpWebRequest)WebRequest.Create(url);
loginRequest.Method = "POST";
loginRequest.CookieContainer = new CookieContainer();
loginRequest.ContentType = "application/x-www-form-urlencoded";
loginRequest.CookieContainer.Add(new Cookie("csrftoken", token, "/", "carkit.kg"));
String postData = "username=" + tempEmail;
postData += "&password=" + tempPass;
postData += "&csrfmiddlewaretoken=" + token;
byte[] data = Encoding.ASCII.GetBytes(postData);
loginRequest.ContentLength = data.Length + 1;
Debug.Log(data.Length);
loginRequest.Timeout = 3000;
String encoded = System.Convert.ToBase64String(System.Text.Encoding.GetEncoding("ISO-8859-1").GetBytes(tempEmail + ":" + tempPass));
loginRequest.Headers.Add("Authorization", "Basic " + encoded);
loginRequest.GetRequestStream().Write(data, 0, data.Length);
loginRequest.PreAuthenticate=true;
HttpWebResponse authResponse = (HttpWebResponse)loginRequest.GetResponse();
But I'm getting error 411 or timed out request. How to get the same result in
C# code as in python?
Answer: I setted [django rest api url](http://www.django-rest-framework.org/api-
guide/authentication/) as simple post request destination and django returned
token in data.
|
How to tell python to reload module whenever it sees import statement
Question: I'm writing a program to manage the flow of processing data. User can write
code of several method to process data, called 'flow code', and tell my
program to compare the result of each method. The code is executed by `exec`.
There's also a git repo containing functions to call, and user can import them
in the 'flow code'.
My question is, because user can change repo between each execution, how to
tell python to reload modules when it sees an import statement in 'flow code'?
My current solution is that, before executing a line, check type of all local
variable of 'flow code' and reload it if the type is `ModuleType`. However,
this is very inefficient. Is there any better solution, like hooks?
Someone said `imputil` can make hooks, but the documentation says:
> Deprecated since version 2.6: The imputil module has been removed in Python
> 3.
And I'm using python 2.7
Answer: Use reload method.
e.g.
>>> import test
>>> test.a
1
>>> test.a = 3
>>> test.a
3
>>> reload(test)
<module 'test' from 'test.pyc'>
>>> test.a
1
>>>
|
a simple python code that astonishingly ignores if condition & statement
Question: I have a really simple code here. But the problem is really bothering me. In
line no 7, there is a if-condition; astonishingly this if condition is never
addressed! I ran the program and checked multiple times using python version
2.7. It behaves as if the if-condition and its statements (along with break)
is inside the comment and is simply ignored.
from random import randint
random_number = randint(1, 10)
guesses_left = 3
while (guesses_left>=1):
print (random_number)
guess = raw_input('Guess ?')
if guess == random_number: #this statement is never checked?
print ('You win!')
break
guesses_left -= 1
else:
print ('You lose.')
Answer:
if guess == random_number: #this statement is never checked?
It _is_ being checked, but it’s just _always_ false.
`guess` is a _string_ since it comes from `raw_input` but `random_number` is
an int coming from `randint`. Since a string can never be equal to an int, the
expression is always false.
You need to convert the input into an int first: `int(guess)`. But make sure
you check for errors when the user does not enter a number.
|
creating daemon using Python libtorrent for fetching meta data of 100k+ torrents
Question: I am trying to fetch meta data of around 10k+ torrents per day using python
libtorrent.
This is the current flow of code
1. Start libtorrent Session.
2. Get total counts of torrents we need metadata for uploaded within last 1 day.
3. get torrent hashes from DB in chunks
4. create magnet link using those hashes and add those magnet URI's in the session by creating handle for each magnet URI.
5. sleep for a second while Meta Data is fetched and keep checking whether meta data s found or not.
6. If meta data is received add it in DB else check if we have been looking for meta data for around 10 minutes , if yes then remove the handle i.e. dont look for metadata no more for now.
7. do above indefinitely. and save session state for future.
so far I have tried this.
#!/usr/bin/env python
# this file will run as client or daemon and fetch torrent meta data i.e. torrent files from magnet uri
import libtorrent as lt # libtorrent library
import tempfile # for settings parameters while fetching metadata as temp dir
import sys #getting arguiments from shell or exit script
from time import sleep #sleep
import shutil # removing directory tree from temp directory
import os.path # for getting pwd and other things
from pprint import pprint # for debugging, showing object data
import MySQLdb # DB connectivity
import os
from datetime import date, timedelta
session = lt.session(lt.fingerprint("UT", 3, 4, 5, 0), flags=0)
session.listen_on(6881, 6891)
session.add_extension('ut_metadata')
session.add_extension('ut_pex')
session.add_extension('smart_ban')
session.add_extension('metadata_transfer')
session_save_filename = "/magnet2torrent/magnet_to_torrent_daemon.save_state"
if(os.path.isfile(session_save_filename)):
fileread = open(session_save_filename, 'rb')
session.load_state(lt.bdecode(fileread.read()))
fileread.close()
print('session loaded from file')
else:
print('new session started')
session.add_dht_router("router.utorrent.com", 6881)
session.add_dht_router("router.bittorrent.com", 6881)
session.add_dht_router("dht.transmissionbt.com", 6881)
session.add_dht_router("dht.aelitis.com", 6881)
session.start_dht()
session.start_lsd()
session.start_upnp()
session.start_natpmp()
alive = True
while alive:
db_conn = MySQLdb.connect( host = '', user = '', passwd = '', db = '', unix_socket='/mysql/mysql.sock') # Open database connection
#print('reconnecting')
#get all records where enabled = 0 and uploaded within yesterday
subset_count = 100 ;
yesterday = date.today() - timedelta(1)
yesterday = yesterday.strftime('%Y-%m-%d %H:%M:%S')
#print(yesterday)
total_count_query = ("SELECT COUNT(*) as total_count FROM content WHERE upload_date > '"+ yesterday +"' AND enabled = '0' ")
#print(total_count_query)
try:
total_count_cursor = db_conn.cursor()# prepare a cursor object using cursor() method
total_count_cursor.execute(total_count_query) # Execute the SQL command
total_count_results = total_count_cursor.fetchone() # Fetch all the rows in a list of lists.
total_count = total_count_results[0]
print(total_count)
except:
print "Error: unable to select data"
total_pages = total_count/subset_count
#print(total_pages)
current_page = 1
while(current_page <= total_pages):
from_count = (current_page * subset_count) - subset_count
#print(current_page)
#print(from_count)
hashes = []
get_mysql_data_query = ("SELECT hash FROM content WHERE upload_date > '" + yesterday +"' AND enabled = '0' ORDER BY record_num DESC LIMIT "+ str(from_count) +" , " + str(subset_count) +" ")
#print(get_mysql_data_query)
try:
get_mysql_data_cursor = db_conn.cursor()# prepare a cursor object using cursor() method
get_mysql_data_cursor.execute(get_mysql_data_query) # Execute the SQL command
get_mysql_data_results = get_mysql_data_cursor.fetchall() # Fetch all the rows in a list of lists.
for row in get_mysql_data_results:
hashes.append(row[0].upper())
except:
print "Error: unable to select data"
#print(hashes)
handles = []
for hash in hashes:
tempdir = tempfile.mkdtemp()
add_magnet_uri_params = {
'save_path': tempdir,
'duplicate_is_error': True,
'storage_mode': lt.storage_mode_t(2),
'paused': False,
'auto_managed': True,
'duplicate_is_error': True
}
magnet_uri = "magnet:?xt=urn:btih:" + hash.upper() + "&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.ccc.de%3A80"
#print(magnet_uri)
handle = lt.add_magnet_uri(session, magnet_uri, add_magnet_uri_params)
handles.append(handle) #push handle in handles list
#print("handles length is :")
#print(len(handles))
while(len(handles) != 0):
for h in handles:
#print("inside handles for each loop")
if h.has_metadata():
torinfo = h.get_torrent_info()
final_info_hash = str(torinfo.info_hash())
final_info_hash = final_info_hash.upper()
torfile = lt.create_torrent(torinfo)
torcontent = lt.bencode(torfile.generate())
tfile_size = len(torcontent)
try:
insert_cursor = db_conn.cursor()# prepare a cursor object using cursor() method
insert_cursor.execute("""INSERT INTO dht_tfiles (hash, tdata) VALUES (%s, %s)""", [final_info_hash , torcontent] )
db_conn.commit()
#print "data inserted in DB"
except MySQLdb.Error, e:
try:
print "MySQL Error [%d]: %s" % (e.args[0], e.args[1])
except IndexError:
print "MySQL Error: %s" % str(e)
shutil.rmtree(h.save_path()) # remove temp data directory
session.remove_torrent(h) # remove torrnt handle from session
handles.remove(h) #remove handle from list
else:
if(h.status().active_time > 600): # check if handle is more than 10 minutes old i.e. 600 seconds
#print('remove_torrent')
shutil.rmtree(h.save_path()) # remove temp data directory
session.remove_torrent(h) # remove torrnt handle from session
handles.remove(h) #remove handle from list
sleep(1)
#print('sleep1')
#print('sleep10')
#sleep(10)
current_page = current_page + 1
#save session state
filewrite = open(session_save_filename, "wb")
filewrite.write(lt.bencode(session.save_state()))
filewrite.close()
print('sleep60')
sleep(60)
#save session state
filewrite = open(session_save_filename, "wb")
filewrite.write(lt.bencode(session.save_state()))
filewrite.close()
I tried kept above script running overnight and found only around 1200
torrent's meta data is found in the overnight session. so I am looking for
improve the performance of the script.
I have even tried Decoding the `save_state` file and noticed there are 700+
`DHT nodes` I am connected to. so its not like `DHT` is not running,
What I am planning to do is, `keep the handles active` in session indefinitely
while meta data is not fetched. and not going to remove the handles after 10
minutes if no meta data is fetched in 10 minutes, like I am currently doing
it.
I have few questions regarding the lib-torrent python bindings.
1. How many handles can I keep running ? is there any limit for running handles ?
2. will running 10k+ or 100k handles slow down my system ? or eat up resources ? if yes then which resources ? I mean RAM , NETWORK ?
3. I am behind firewall , can be a blocked incoming port causing the slow speed of metadata fetching ?
4. can DHT server like router.bittorrent.com or any other BAN my ip address for sending too many requests ?
5. Can other peers BAN my ip address if they find out I am making too many requests only fot fetching meta data ?
6. can I run multiple instances of this script ? or may be multi-threading ? will it give better performance ?
7. if using multiple instances of the same script, each script will get unique node-id depending on the ip and port I am using , is this viable solution ?
Is there any better approach ? for achieving what I am trying ?
Answer: I can't answer questions specific to libtorrent's APIs, but some of your
questions apply to bittorrent in general.
> will running 10k+ or 100k handles slow down my system ? or eat up resources
> ? if yes then which resources ? i mean RAM , NETWORK ?
Metadata-downloads shouldn't use much resources since they are not full
torrent-downloads yet, i.e. they can't allocate the actual files or anything
like that. But they will need some ram/disk space for the metadata itself once
they grab the first chunk of those.
> I am behind firewall , can be a blocked incoming port causing the slow speed
> of metadata fetching ?
yes, by reducing the number of peers that can establish connections it becomes
more difficult to fetch metadata (or establish any connection at all) on
swarms with a low peer count.
NATs can cause the same issue.
> can DHT server like router.bittorrent.com or any other BAN my ip address for
> sending too many requests ?
router.bittorrent.com is a bootstrap node, not a server per se. Lookups don't
query a single node, they query many different (among millions). But yes,
individual nodes can ban, or more likely rate-limit, you.
This can be mitigated by looking for randomly distributed IDs to spread the
load across the DHT keyspace.
> can i run multiple instances of this script ? or may be multi-threading ?
> will it give better performance ?
AIUI libtorrent is sufficiently non-blocking or multi-threaded that you can
schedule many torrents at once.
I don't know if libtorrent has a rate-limit for outgoing DHT requests.
> if using multiple instances of the same script, each script will get unique
> node-id depending on the ip and port i am using , is this viable solution ?
If you mean the DHT node ID, then they're derived from the IP (as per [BEP
42](http://bittorrent.org/beps/bep_0042.html)), not the port. Although some
random element is included, so a limited amount of IDs can be obtained per IP.
And some of this might also might be applicable for your scenario:
<http://blog.libtorrent.org/2012/01/seeding-a-million-torrents/>
And another option is [my own DHT
implementation](https://github.com/the8472/mldht) which includes a CLI to
bulk-fetch torrents.
|
Cannot import pathos in Python
Question:
import pathos
import pathos.multiprocessing as mp
import dill
print pool.map(pow, [1,2,3,4], [5,6,7,8])
when i run the above code it throws a error
> cannot find pathos.multiprocessing
>
> cannot import pathos
i tried all the possible ways but i could not find any solution. I was trying
to work on a developing a code which takes more than 10 inputs and process
them using multiprocessing instead of waiting in queue and generates output.
For that i have tried multiprocessing, but it throws pickling error, so i
tried to use pathos, but it says cannot import pathos. Can any one tell me the
possible solution for this???
Answer: You need to **install** the software you use, otherwise you can't use it.
So, go ahead and install pathos.
|
StackOverflowError when using getattr in Jython
Question: I'm writing a text editor in Jython. This text editor has a toolbar which is
displayed with a `ToolbarView` class and handled by a `ToolbarController`
class. Some actions can't be dealt with by the `ToolbarController` on its own,
so these are delegated to the `MainController` class.
To avoid repeating code since there are many actions delegated from the
`ToolbarController` to the MainController, I've used getattr as suggested in a
previous question I asked
[here](http://stackoverflow.com/questions/32828305/setattr-and-getattr-with-
methods). I have also realised I can use the same mechanism in the
`ToolbarView` code for the actions of the buttons, but I can't get it to work
and I end up getting an infinite loop and a `Java StackOverflowError`.
This is an extract of the relevant code:
**ToolbarView** class:
from javax.swing import JToolBar, ImageIcon, JButton
class ToolbarView(JToolBar):
def __init__(self, controller):
#Give reference to controller to delegate action response
self.controller = controller
options= ['NewFile', 'OpenFile', 'SaveFile', 'CloseFile']
for option in options:
methods[option] = "on" + option + "Click"
print methods[option]
for name, method in methods.items():
button = JButton(name, actionPerformed=getattr(self, method))
self.add(button)
def __getattr__(self, name):
return getattr(self.controller, name)
**ToolbarController** class:
from .ToolbarView import ToolbarView
class ToolbarController(object):
def __init__(self, mainController):
#Create view with a reference to its controller to handle events
self.view = ToolbarView(self)
#Will also need delegating to parent presenter
self.mainController = mainController
def __getattr__(self, name):
return getattr(self.mainController, name)
**MainController** class:
from .ToolbarController import ToolbarController
class MainController(object):
def __init__(self):
self.toolbarController = ToolbarController(self)
def onNewFileClick(self, event):
print("MainController: Creating new file...")
def onEditFileClick(self, event):
print("MainController: Editting new file...")
def onSaveFileClick(self, event):
print("MainController: Saving new file...")
def onCloseFileClick(self, event):
print("MainController: Closing new file...")
So what I expect is when I click the button, `MainController.onNewFileClick`
gets executed and prints out that message in console. It works if I want to
delegate from the `ToolbarView` to the `ToolbarController`, but it doesn't
work when I pass that delegation from the `ToolbarController` to the
MainController. It seems to call itself on an infinite loop. The error I get
is:
Traceback (most recent call last):
File "main.py", line 3, in <module>
MainController()
File "/home/training/Jython/controller/MainController", line 8, in __init__
self.toolbarController = ToolbarController(self)
File "/home/Jython/controller/ToolbarController.py", line 8, in __init__
self.view = ToolbarView(self)
File "/home/Jython/controller/ToolbarView.py", line 44, in __init__
button = JButton(name, actionPerformed=getattr(self, method))
File "/home/Jython/controller/ToolbarView.py", line 54, in __getattr__
return getattr(self.controller, name)
File "/home/Jython/controller/ToolbarController.py", line 15, in __getattr__
return getattr(self.mainController, name)
File "/home/Jython/controller/ToolbarController.py", line 15, in __getattr__
return getattr(self.mainController, name)
[...]
File "/home/Jython/controller/ToolbarController.py", line 15, in __getattr__
return getattr(self.mainController, name)
RuntimeError: maximum recursion depth exceeded (Java StackOverflowError)
What am I doing wrong? I've tried something similar in python (delegating from
a class to another class to another class) and it works if a put `()` after
the getattr, but here I get confused because of the `actionPerformed` in the
JButton. I've tried it but results are the same.
Answer: it seems you are using `Jython`, which i don't really know. anyways, in
python, you override `__getattr__`, then you should expect `getattr` to use
your overridden hook instead. so i think you really mean:
class ToolbarView(JToolBar):
def __init__(self, controller):
#Give reference to controller to delegate action response
self.controller = controller
options= ['NewFile', 'OpenFile', 'SaveFile', 'CloseFile']
for option in options:
methods[option] = "on" + option + "Click"
print methods[option]
for name, method in methods.items():
button = JButton(name, actionPerformed=super(ToolbarView, self).__getattr__(method))
self.add(button)
def __getattr__(self, name):
return getattr(self.controller, name)
watch how buttons are created.
in terms of why you have a SO problem, it is because how `getattr` is handled.
if you override `__getattr__`, this hook will only get called if you try to
reference to a undefined field:
>>> class A(object):
defined = True
def __getattr__(self, name):
print "referenced :" + name
>>> a = A()
>>> a.defined
True
>>> a.undefined
referenced :undefined
hope it's clear how the hook work now.
so the SO is actually caused by you were referencing something that does not
belong to `MainController`.
in your `MainController`, only `onNewFileClick` is defined, but you defined 3
other options:
options= ['NewFile', 'OpenFile', 'SaveFile', 'CloseFile']
so, this will happen at the second round of iteration. since `MainController`
has no `onOpenFileClick`, an `AttributeError` will be raised, but captured by
`ToolbarController`, and therefore the overridden `__getattr__` is invoked and
on and on. that's why your call stack explodes.
|
Print list without space in i python-notebook
Question:
a="alizafar"
b=len(a)
lis=[1]*b
d=b
sep=""
c=0
while b>0:
lis[c]=a[c]
c=c+1
b=b-1
c=0
while d>0:
new=lis[c]
print new,
c=c+1
d=d-1
result: a l i z a f a r
while I want to print: alizafar
Answer: You can use `sys.stdout.write` instead of `print`
import sys
a="alizafar"
b=len(a)
lis=[1]*b
d=b
sep=""
c=0
while b>0:
lis[c]=a[c]
c=c+1
b=b-1
c=0
while d>0:
new=lis[c]
sys.stdout.write(new)
c=c+1
d=d-1
will print out
alizafar
|
Path manipulation
Question: Consider you are launching a script in the following linux path:
`/home/chris/sources/a/b/c/d/e/test.py`
I want to be able to check whether folder named `sources` is in path and then
return the path `/home/chris/sources/`
Do you think I should do it using simple string manipulation, or do we have in
python some xpath library that can help me do it?
Answer: inb4Padraic
path = '/home/chris/sources/a/b/c/d/e/test.py'.split('/')
if 'sources' in path:
print '/'.join(path[:path.index('sources') + 1])
another way
import os
path = '/home/chris/sources/a/b/c/d/e/test.py'.split('sources')
if len(path) > 1:
print os.path.join(path[0], 'sources')
|
On Centos Linux, how to install Python package 'readline' using pip?
Question: Using the regular command `sudo pip install readline` I got an error
Command "/usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-Ax57Qh/readline/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-KRvGg7-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-Ax57Qh/readline
The complete console output is
sudo pip install readline
[sudo] password for qazwsx:
Collecting readline
Using cached readline-6.2.4.1.tar.gz
Installing collected packages: readline
Running setup.py install for readline
Complete output from command /usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-Ax57Qh/readline/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-KRvGg7-record/install-record.txt --single-version-externally-managed --compile:
readline-6.2/
readline-6.2/doc/
readline-6.2/doc/Makefile.in
readline-6.2/doc/texinfo.tex
readline-6.2/doc/version.texi
readline-6.2/doc/fdl.texi
readline-6.2/doc/rlman.texi
readline-6.2/doc/rltech.texi
readline-6.2/doc/rluser.texi
readline-6.2/doc/rluserman.texi
readline-6.2/doc/history.texi
readline-6.2/doc/hstech.texi
readline-6.2/doc/hsuser.texi
readline-6.2/doc/readline.3
readline-6.2/doc/history.3
readline-6.2/doc/texi2dvi
readline-6.2/doc/texi2html
readline-6.2/doc/readline.ps
readline-6.2/doc/history.ps
readline-6.2/doc/rluserman.ps
readline-6.2/doc/readline.dvi
readline-6.2/doc/history.dvi
readline-6.2/doc/rluserman.dvi
readline-6.2/doc/readline.info
readline-6.2/doc/history.info
readline-6.2/doc/rluserman.info
readline-6.2/doc/readline.html
readline-6.2/doc/history.html
readline-6.2/doc/rluserman.html
readline-6.2/doc/readline.0
readline-6.2/doc/history.0
readline-6.2/doc/readline_3.ps
readline-6.2/doc/history_3.ps
readline-6.2/doc/history.pdf
readline-6.2/doc/readline.pdf
readline-6.2/doc/rluserman.pdf
readline-6.2/examples/
readline-6.2/examples/autoconf/
readline-6.2/examples/autoconf/BASH_CHECK_LIB_TERMCAP
readline-6.2/examples/autoconf/RL_LIB_READLINE_VERSION
readline-6.2/examples/autoconf/wi_LIB_READLINE
readline-6.2/examples/rlfe/
readline-6.2/examples/rlfe/ChangeLog
readline-6.2/examples/rlfe/Makefile.in
readline-6.2/examples/rlfe/README
readline-6.2/examples/rlfe/config.h.in
readline-6.2/examples/rlfe/configure
readline-6.2/examples/rlfe/configure.in
readline-6.2/examples/rlfe/extern.h
readline-6.2/examples/rlfe/os.h
readline-6.2/examples/rlfe/pty.c
readline-6.2/examples/rlfe/rlfe.c
readline-6.2/examples/rlfe/screen.h
readline-6.2/examples/Makefile.in
readline-6.2/examples/excallback.c
readline-6.2/examples/fileman.c
readline-6.2/examples/manexamp.c
readline-6.2/examples/readlinebuf.h
readline-6.2/examples/rl-fgets.c
readline-6.2/examples/rlcat.c
readline-6.2/examples/rlevent.c
readline-6.2/examples/rltest.c
readline-6.2/examples/rl.c
readline-6.2/examples/rlptytest.c
readline-6.2/examples/rlversion.c
readline-6.2/examples/histexamp.c
readline-6.2/examples/Inputrc
readline-6.2/examples/rlwrap-0.30.tar.gz
readline-6.2/support/
readline-6.2/support/config.guess
readline-6.2/support/config.rpath
readline-6.2/support/config.sub
readline-6.2/support/install.sh
readline-6.2/support/mkdirs
readline-6.2/support/mkdist
readline-6.2/support/mkinstalldirs
readline-6.2/support/shobj-conf
readline-6.2/support/shlib-install
readline-6.2/support/wcwidth.c
readline-6.2/shlib/
readline-6.2/shlib/Makefile.in
readline-6.2/COPYING
readline-6.2/README
readline-6.2/MANIFEST
readline-6.2/INSTALL
readline-6.2/CHANGELOG
readline-6.2/CHANGES
readline-6.2/NEWS
readline-6.2/USAGE
readline-6.2/aclocal.m4
readline-6.2/config.h.in
readline-6.2/configure
readline-6.2/configure.in
readline-6.2/Makefile.in
readline-6.2/ansi_stdlib.h
readline-6.2/chardefs.h
readline-6.2/history.h
readline-6.2/histlib.h
readline-6.2/keymaps.h
readline-6.2/posixdir.h
readline-6.2/posixjmp.h
readline-6.2/readline.h
readline-6.2/posixselect.h
readline-6.2/posixstat.h
readline-6.2/rlconf.h
readline-6.2/rldefs.h
readline-6.2/rlmbutil.h
readline-6.2/rlprivate.h
readline-6.2/rlshell.h
readline-6.2/rlstdc.h
readline-6.2/rltty.h
readline-6.2/rltypedefs.h
readline-6.2/rlwinsize.h
readline-6.2/tcap.h
readline-6.2/tilde.h
readline-6.2/xmalloc.h
readline-6.2/bind.c
readline-6.2/callback.c
readline-6.2/compat.c
readline-6.2/complete.c
readline-6.2/display.c
readline-6.2/emacs_keymap.c
readline-6.2/funmap.c
readline-6.2/input.c
readline-6.2/isearch.c
readline-6.2/keymaps.c
readline-6.2/kill.c
readline-6.2/macro.c
readline-6.2/mbutil.c
readline-6.2/misc.c
readline-6.2/nls.c
readline-6.2/parens.c
readline-6.2/readline.c
readline-6.2/rltty.c
readline-6.2/savestring.c
readline-6.2/search.c
readline-6.2/shell.c
readline-6.2/signals.c
readline-6.2/terminal.c
readline-6.2/text.c
readline-6.2/tilde.c
readline-6.2/undo.c
readline-6.2/util.c
readline-6.2/vi_keymap.c
readline-6.2/vi_mode.c
readline-6.2/xfree.c
readline-6.2/xmalloc.c
readline-6.2/history.c
readline-6.2/histexpand.c
readline-6.2/histfile.c
readline-6.2/histsearch.c
readline-6.2/patchlevel
patching file vi_mode.c
patching file callback.c
patching file support/shobj-conf
patching file patchlevel
patching file input.c
patching file patchlevel
patching file vi_mode.c
patching file patchlevel
checking build system type... x86_64-unknown-linux-gnu
checking host system type... x86_64-unknown-linux-gnu
Beginning configuration for readline-6.2 for x86_64-unknown-linux-gnu
checking whether make sets $(MAKE)... yes
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking minix/config.h usability... no
checking minix/config.h presence... no
checking for minix/config.h... no
checking whether it is safe to define __EXTENSIONS__... yes
checking whether gcc needs -traditional... no
checking for a BSD-compatible install... /usr/bin/install -c
checking for ar... ar
checking for ranlib... ranlib
checking for an ANSI C-conforming const... yes
checking for function prototypes... yes
checking whether char is unsigned... no
checking for working volatile... yes
checking return type of signal handlers... void
checking for size_t... yes
checking for ssize_t... yes
checking for ANSI C header files... (cached) yes
checking whether stat file-mode macros are broken... no
checking for dirent.h that defines DIR... yes
checking for library containing opendir... none required
checking for fcntl... yes
checking for kill... yes
checking for lstat... yes
checking for memmove... yes
checking for putenv... yes
checking for select... yes
checking for setenv... yes
checking for setlocale... yes
checking for strcasecmp... yes
checking for strpbrk... yes
checking for tcgetattr... yes
checking for vsnprintf... yes
checking for isascii... yes
checking for isxdigit... yes
checking for getpwent... yes
checking for getpwnam... yes
checking for getpwuid... yes
checking for working strcoll... yes
checking fcntl.h usability... yes
checking fcntl.h presence... yes
checking for fcntl.h... yes
checking for unistd.h... (cached) yes
checking for stdlib.h... (cached) yes
checking varargs.h usability... no
checking varargs.h presence... no
checking for varargs.h... no
checking stdarg.h usability... yes
checking stdarg.h presence... yes
checking for stdarg.h... yes
checking for string.h... (cached) yes
checking for strings.h... (cached) yes
checking limits.h usability... yes
checking limits.h presence... yes
checking for limits.h... yes
checking locale.h usability... yes
checking locale.h presence... yes
checking for locale.h... yes
checking pwd.h usability... yes
checking pwd.h presence... yes
checking for pwd.h... yes
checking for memory.h... (cached) yes
checking termcap.h usability... no
checking termcap.h presence... no
checking for termcap.h... no
checking termios.h usability... yes
checking termios.h presence... yes
checking for termios.h... yes
checking termio.h usability... yes
checking termio.h presence... yes
checking for termio.h... yes
checking sys/pte.h usability... no
checking sys/pte.h presence... no
checking for sys/pte.h... no
checking sys/stream.h usability... no
checking sys/stream.h presence... no
checking for sys/stream.h... no
checking sys/select.h usability... yes
checking sys/select.h presence... yes
checking for sys/select.h... yes
checking sys/file.h usability... yes
checking sys/file.h presence... yes
checking for sys/file.h... yes
checking for sys/ptem.h... no
checking for special C compiler options needed for large files... no
checking for _FILE_OFFSET_BITS value needed for large files... no
checking for type of signal functions... posix
checking if signal handlers must be reinstalled when invoked... no
checking for presence of POSIX-style sigsetjmp/siglongjmp... present
checking for lstat... yes
checking whether or not strcoll and strcmp differ... no
checking whether the ctype macros accept non-ascii characters... yes
checking whether getpw functions are declared in pwd.h... yes
checking whether termios.h defines TIOCGWINSZ... no
checking whether sys/ioctl.h defines TIOCGWINSZ... yes
checking for sig_atomic_t in signal.h... yes
checking whether signal handlers are of type void... yes
checking for TIOCSTAT in sys/ioctl.h... no
checking for FIONREAD in sys/ioctl.h... yes
checking for speed_t in sys/types.h... no
checking for struct winsize in sys/ioctl.h and termios.h... sys/ioctl.h
checking for struct dirent.d_ino... yes
checking for struct dirent.d_fileno... yes
checking for tgetent... no
checking for tgetent in -ltermcap... no
checking for tgetent in -ltinfo... no
checking for tgetent in -lcurses... no
checking for tgetent in -lncurses... no
checking which library has the termcap functions... using gnutermcap
checking wctype.h usability... yes
checking wctype.h presence... yes
checking for wctype.h... yes
checking wchar.h usability... yes
checking wchar.h presence... yes
checking for wchar.h... yes
checking langinfo.h usability... yes
checking langinfo.h presence... yes
checking for langinfo.h... yes
checking for mbrlen... yes
checking for mbscasecmp... no
checking for mbscmp... no
checking for mbsnrtowcs... yes
checking for mbsrtowcs... yes
checking for mbschr... no
checking for wcrtomb... yes
checking for wcscoll... yes
checking for wcsdup... yes
checking for wcwidth... yes
checking for wctype... yes
checking for wcswidth... yes
checking whether mbrtowc and mbstate_t are properly declared... yes
checking for iswlower... yes
checking for iswupper... yes
checking for towlower... yes
checking for towupper... yes
checking for iswctype... yes
checking for nl_langinfo and CODESET... yes
checking for wchar_t in wchar.h... yes
checking for wctype_t in wctype.h... yes
checking for wint_t in wctype.h... yes
checking configuration for building shared libraries... supported
configure: creating ./config.status
config.status: creating Makefile
config.status: creating doc/Makefile
config.status: creating examples/Makefile
config.status: creating shlib/Makefile
config.status: creating config.h
config.status: executing default commands
rm -f readline.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O readline.c
rm -f vi_mode.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O vi_mode.c
rm -f funmap.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O funmap.c
rm -f keymaps.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O keymaps.c
rm -f parens.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O parens.c
rm -f search.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O search.c
rm -f rltty.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O rltty.c
rm -f complete.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O complete.c
rm -f bind.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O bind.c
rm -f isearch.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O isearch.c
rm -f display.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O display.c
rm -f signals.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O signals.c
rm -f util.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O util.c
rm -f kill.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O kill.c
rm -f undo.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O undo.c
rm -f macro.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O macro.c
rm -f input.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O input.c
rm -f callback.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O callback.c
rm -f terminal.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O terminal.c
rm -f text.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O text.c
rm -f nls.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O nls.c
rm -f misc.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O misc.c
rm -f compat.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O compat.c
rm -f xfree.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O xfree.c
rm -f xmalloc.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O xmalloc.c
rm -f history.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O history.c
rm -f histexpand.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O histexpand.c
rm -f histfile.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O histfile.c
rm -f histsearch.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O histsearch.c
rm -f shell.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O shell.c
rm -f mbutil.o
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O mbutil.c
rm -f tilde.o
gcc -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -g -O -DREADLINE_LIBRARY -c ./tilde.c
rm -f libreadline.a
ar cr libreadline.a readline.o vi_mode.o funmap.o keymaps.o parens.o search.o rltty.o complete.o bind.o isearch.o display.o signals.o util.o kill.o undo.o macro.o input.o callback.o terminal.o text.o nls.o misc.o compat.o xfree.o xmalloc.o history.o histexpand.o histfile.o histsearch.o shell.o mbutil.o tilde.o
test -n "ranlib" && ranlib libreadline.a
rm -f libhistory.a
ar cr libhistory.a history.o histexpand.o histfile.o histsearch.o shell.o mbutil.o xmalloc.o xfree.o
test -n "ranlib" && ranlib libhistory.a
test -d shlib || mkdir shlib
( cd shlib ; make all )
make[1]: Entering directory `/tmp/pip-build-Ax57Qh/readline/rl/readline-lib/shlib'
rm -f readline.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o readline.o ../readline.c
mv readline.o readline.so
rm -f vi_mode.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o vi_mode.o ../vi_mode.c
mv vi_mode.o vi_mode.so
rm -f funmap.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o funmap.o ../funmap.c
mv funmap.o funmap.so
rm -f keymaps.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o keymaps.o ../keymaps.c
mv keymaps.o keymaps.so
rm -f parens.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o parens.o ../parens.c
mv parens.o parens.so
rm -f search.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o search.o ../search.c
mv search.o search.so
rm -f rltty.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o rltty.o ../rltty.c
mv rltty.o rltty.so
rm -f complete.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o complete.o ../complete.c
mv complete.o complete.so
rm -f bind.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o bind.o ../bind.c
mv bind.o bind.so
rm -f isearch.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o isearch.o ../isearch.c
mv isearch.o isearch.so
rm -f display.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o display.o ../display.c
mv display.o display.so
rm -f signals.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o signals.o ../signals.c
mv signals.o signals.so
rm -f util.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o util.o ../util.c
mv util.o util.so
rm -f kill.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o kill.o ../kill.c
mv kill.o kill.so
rm -f undo.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o undo.o ../undo.c
mv undo.o undo.so
rm -f macro.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o macro.o ../macro.c
mv macro.o macro.so
rm -f input.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o input.o ../input.c
mv input.o input.so
rm -f callback.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o callback.o ../callback.c
mv callback.o callback.so
rm -f terminal.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o terminal.o ../terminal.c
mv terminal.o terminal.so
rm -f text.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o text.o ../text.c
mv text.o text.so
rm -f nls.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o nls.o ../nls.c
mv nls.o nls.so
rm -f misc.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o misc.o ../misc.c
mv misc.o misc.so
rm -f xmalloc.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o xmalloc.o ../xmalloc.c
mv xmalloc.o xmalloc.so
rm -f xfree.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o xfree.o ../xfree.c
mv xfree.o xfree.so
rm -f history.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o history.o ../history.c
mv history.o history.so
rm -f histexpand.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o histexpand.o ../histexpand.c
mv histexpand.o histexpand.so
rm -f histfile.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o histfile.o ../histfile.c
mv histfile.o histfile.so
rm -f histsearch.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o histsearch.o ../histsearch.c
mv histsearch.o histsearch.so
rm -f shell.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o shell.o ../shell.c
mv shell.o shell.so
rm -f mbutil.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o mbutil.o ../mbutil.c
mv mbutil.o mbutil.so
rm -f tilde.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -DREADLINE_LIBRARY -c -o tilde.o ../tilde.c
mv tilde.o tilde.so
rm -f compat.so
gcc -c -DHAVE_CONFIG_H -DNEED_EXTERN_PC -fPIC -I. -I.. -I.. -DRL_LIBRARY_VERSION='"6.2"' -g -O -fPIC -o compat.o ../compat.c
mv compat.o compat.so
rm -f libreadline.so.6.2
gcc -shared -Wl,-soname,libreadline.so.6.2 -L./lib/termcap -Wl,-rpath,/usr/local/lib -Wl,-soname,`basename libreadline.so.6.2 .2` -o libreadline.so.6.2 readline.so vi_mode.so funmap.so keymaps.so parens.so search.so rltty.so complete.so bind.so isearch.so display.so signals.so util.so kill.so undo.so macro.so input.so callback.so terminal.so text.so nls.so misc.so xmalloc.so xfree.so history.so histexpand.so histfile.so histsearch.so shell.so mbutil.so tilde.so compat.so
rm -f libhistory.so.6.2
gcc -shared -Wl,-soname,libhistory.so.6.2 -L./lib/termcap -Wl,-rpath,/usr/local/lib -Wl,-soname,`basename libhistory.so.6.2 .2` -o libhistory.so.6.2 history.so histexpand.so histfile.so histsearch.so shell.so mbutil.so xmalloc.so xfree.so
make[1]: Leaving directory `/tmp/pip-build-Ax57Qh/readline/rl/readline-lib/shlib'
============ Building the readline library ============
============ Building the readline extension module ============
running install
running build
running build_ext
building 'readline' extension
creating build
creating build/temp.linux-x86_64-2.7
creating build/temp.linux-x86_64-2.7/Modules
creating build/temp.linux-x86_64-2.7/Modules/2.x
gcc -pthread -fno-strict-aliasing -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -DHAVE_RL_CALLBACK -DHAVE_RL_CATCH_SIGNAL -DHAVE_RL_COMPLETION_APPEND_CHARACTER -DHAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK -DHAVE_RL_COMPLETION_MATCHES -DHAVE_RL_COMPLETION_SUPPRESS_APPEND -DHAVE_RL_PRE_INPUT_HOOK -I. -I/usr/include/python2.7 -c Modules/2.x/readline.c -o build/temp.linux-x86_64-2.7/Modules/2.x/readline.o -Wno-strict-prototypes
Modules/2.x/readline.c:8:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
compilation terminated.
error: command 'gcc' failed with exit status 1
----------------------------------------
Command "/usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-Ax57Qh/readline/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-KRvGg7-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-Ax57Qh/readline
**Update** : adding path to `$CPATH` does NOT help
-bash-4.2$ locate Python.h
/usr/include/python2.7/Python.h
-bash-4.2$ echo $CPATH
-bash-4.2$ export CPATH=/usr/include/python2.7/
-bash-4.2$ echo $CPATH
/usr/include/python2.7/
and I still get the _same_ error running `sudo pip install readline`:
Command "/usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-NP1WUS/readline/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-9Uamrv-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-NP1WUS/readline
Then the said file no longer exist in tmp/:
-bash-4.2$ ls -la /tmp/pip-build-*
ls: cannot access /tmp/pip-build-*: No such file or directory
Answer: Don't know for sure but:
Try installing `sudo yum install python-devel`
EDIT: Can you check if the directory /usr/include/python2.7 actually exists?
Looks like gcc can't find the libraries for Python.
|
Certain Amount of Time to Input in Python?
Question: I'm making a simple Python Text Adventure Game, and I want to know a way how
to make a simple function that asks for a user input; however, I want the
program to ONLY accept the input before a certain duration (in my program I'm
using 3 seconds). Furthermore, I want the function to check the correctness of
the input before accepting it as right. My attempt is as follows:
lvl1 = [
'Hi', 'Friend', 'Say', 'Smelly',
'Made', 'Tree', 'Python', 'Freak'
]
one = raw_input("You have 3 seconds to type: " + random.choice(lvl1))
endtime = time.time() + 3
while time.time() <= endtime and lvl1[0:]:
print("Wrong!")
one = raw_input("Try again: ")
print("Correct")
Basically what I want this code to do is to get an input from the user in
(less than or equal to) a 3 second time duration, but before congratulating
the user, make sure that their input is the same as one of the strings in the
'lvl1' array.
Thanks!
Answer: You were very close. One thing that you missed was that you need to start the
timer before you prompt the user for input. If you do not do this, the program
will wait for the users input before starting the timer, which will always
cause the "in less than 3 seconds" condition to be true. Another change I made
was storing the value of the randomly selected word so that you can display it
and, later in the program, verify that the user's input matches later.
import random
import time
lvl1 = [
'Hi', 'Friend', 'Say', 'Smelly',
'Made', 'Tree', 'Python', 'Freak'
]
word = random.choice(lvl1)
start_time = time.time()
one = raw_input("You have 3 seconds to type: {}\n".format(word))
while time.time() - start_time > 3 or one != word:
print("Wrong!")
start_time = time.time()
one = raw_input("Try again: ")
print("Correct")
Hope this helps!
|
Privlege error trying to create symlink using python on windows 10
Question: I am attempting to create a symlink using python on windows 10 (home version)
with the foll. code:
import ctypes
kdll = ctypes.windll.LoadLibrary("kernel32.dll")
kdll.CreateSymbolicLinkW(src_dir, dst_dir, 1)
but I get the foll. error:
*** error: (1314, 'CreateSymbolicLink', 'A required privilege is not held by the client.')
How to fix this?
Answer: If UAC is enabled and your user is an administrator, then the Local Security
Authority (LSA, hosted in lsass.exe) logs your user on with a restricted
access token. For this token, the `BUILTIN\Administrators` group is used only
for denying access; the integrity-level label is medium instead of high; and
the privileges typically granted to an administrator have been filtered out.
To create a symbolic link, you need to create the process using your
unrestricted/elevated access token (i.e. elevated from medium to high
integrity level). Do this by right-clicking and selecting "Run as
administrator". This elevated token will be inherited by child processes, so
it suffices to run your Python script from an elevated command prompt, which
you can open via the keyboard shortcut `Win+X` `A`. You can verify that the
cmd shell is elevated by running `whoami /priv` and checking for the presence
of `SeCreateSymbolicLinkPrivilege`. Don't be alarmed if the state is disabled.
The Windows [`CreateSymbolicLink`](https://msdn.microsoft.com/en-
us/library/aa363866) function automatically enables this privilege.
That said, since you're creating a _directory_ symbolic link, then perhaps a
junction will work just as well. No special privilege is required to create a
junction. You can create a junction using cmd's `mklink` command. For example:
subprocess.check_call('mklink /J "%s" "%s"' % (link, target), shell=True)
|
Import JSON to MONGODB
Question: I have a Python script that generates a huge JSON. When I put the program to
run, it generates a file in Notepad with JSON. I wanted to put this JSON in
MongoDB database and let stored, and then be able to search this JSON using
MongoDB commands to search for espercificas things. But could not find
anywhere how can I get this JSON file in the Notepad, and put in the database.
If anyone can help.
tanks
Answer: Go to file directory using cmd, outside mongoshell. Then,
mongoimport --db dbName --collection collectionName <fileName.json
Example,
mongoimport --db foo --collection myCollections < /Users/file.json
connected to: *.*.*.*
Sat Mar 2 15:01:08 imported 11 objects
|
I got stuck on Python error TypeError: unhashable type: 'slice'
Question:
from informedSearch import *
from search import *
class EightPuzzleProblem(InformedProblemState):
"""
Inherited from the InformedProblemState class. To solve
the eight puzzle problem.
"""
def __init__(self, myList, list = {}, operator = None):
self.myList = list
self.operator = operator
def __str__(self):
## Method returns a string representation of the state.
result = ""
if self.operator != None:
result += "Operator: " + self.operator + ""
result += " " + ' '.join(self.myList[0:3]) + "\n"
result += " " + ' '.join(self.myList[3:6]) + "\n"
result += " " + ' '.join(self.myList[6:9]) + "\n"
return result
def illegal(self):
## Tests whether the state is illegal.
if self.myList < 0 or self.myList > 9: return 1
return 0
def equals(self, state):
## Method to determine whether the state instance
## and the given state are equal.
return ' '.join(self.myList) == ' '.join(state.myList)
## The five methods below perform the tree traversing
def move(self, value):
nList = self.myList[:] # make copy of the current state
position = nList.index('P') # P acts as the key
val = nList.pop(position + value)
nList.insert(position + value, 'P')
nList.pop(position)
nList.insert(position, val)
return nList
def moveleft(self):
n = self.move(-1)
return EightPuzzleProblem(n, "moveleft")
def moveright(self):
n = self.move(1)
return EightPuzzleProblem(n, "moveright")
def moveup(self):
n = self.move(-3)
return EightPuzzleProblem(n, "moveup")
def movedown(self):
n = self.move(+3)
return EightPuzzleProblem(n, "movedown")
def operatorNames(self):
return ["moveleft", "moveright", "moveup", "movedown"]
def enqueue(self):
q = []
if (self.myList.index('P') != 0) and (self.myList.index('P') != 3) and (self.myList.index('P') != 6):
q.append(self.moveleft())
if (self.myList.index('P') != 2) and (self.myList.index('P') != 5) and (self.myList.index('P') != 8):
q.append(self.moveright())
if self.myList.index('P') >= 3:
q.append(self.moveup())
if self.myList.index('P') >= 5:
q.append(self.movedown())
def applyOperators(self):
return [self.moveleft(), self.moveright(), self.moveup(), self.movedown()]
def heuristic():
counter = 0
for i in range(len(self.myList)):
if ((self.myList[i] != goal.myList[i]) and self.myList[i] != 'P'):
## Position of current:
current = goal.myList.index(self.myList[i])
if current < 3: goalRow = 0
elif current < 6: goalRow = 1
else: goalRow = 2
if i < 3: initRow = 0
elif i < 6: initRow = 1
else: startRow = 2
initColumn = i % 3
goalColumn = current % 3
counter += (abs(goalColumn - initColumn) + abs(goalRow - initRow))
return counter
#Uncomment to test the starting states:
init = ['1','3','P','8','2','4','7','6','5'] #A
#init = ['1','3','4','8','6','2','P','7','5'] #B
#init = ['P','1','3','4','2','5','8','7','6'] #C
#init = ['7','1','2','8','P','3','6','5','4'] #D
#init = ['8','1','2','7','P','4','6','5','3'] #E
#init = ['2','6','3','4','P','5','1','8','7'] #F
#init = ['7','3','4','6','1','5','8','P','2'] #G
#init = ['7','4','5','6','P','3','8','1','2'] #H
goal = ['1','2','3','8','P','4','7','6','5'] #goal state
InformedSearch(EightPuzzleProblem(init), EightPuzzleProblem(goal))
I run it and it shows error **line 34, in __str__ result += " " + '
'.join(self.myList[0:3]) + "\n" TypeError: unhashable type: 'slice'** Can
anyone help please? I think there are a lot of other problems in this class
too.
Answer: You're setting the "list" to a dictionary as a default value: `list = {}` in:
def __init__(self, myList, list = {}, operator = None):
and then assigning it to `myList` with:
self.myList = list
A dictionary cannot be sliced like a list. So when you try to slice it:
self.myList[0:3]
it fails.
|
Using Python and external programs
Question: By using python, how do I use cmd.exe supported commands and get the output to
be viewed back in python? The reason I am doing this is to get the Microsoft
.NET framework version. At the moment I could only find it through the cmd.exe
by using the following command:
wmic product where "Name like 'Microsoft .Net%'" get Name, Version
So I was thinking to get python to execute the above command and get the
results back and write them to a file.
Answer: Here is a way about how to execute cmd command from python using the
[subprocess](https://docs.python.org/2/library/subprocess.html#module-
subprocess) module.
**Code** : The following code is just pinging the loopback address using `ping
127.0.0.1` command and then writing the results to a file.
[Docs](https://docs.python.org/2/tutorial/inputoutput.html#reading-and-
writing-files) for file handling in python could be found
[here](https://docs.python.org/2/tutorial/inputoutput.html#reading-and-
writing-files).
import subprocess
def myFunc():
p = subprocess.Popen("ping 127.0.0.1", stdout=subprocess.PIPE, stderr=subprocess.PIPE)
out, err = p.communicate()
print out
print err
with open('myOutputFile.txt', 'w') as f:
f.write(out) #Write the output to a file
myFunc()
Replace the `ping 127.0.0.1` with other cmd command and it should work. For
eg: `netstat -a`.
Note: It might take a while before you see the output in console, because the
output will be returned to the console when the cmd command has finished the
execution!
The following code should do your job:
import subprocess
def myFunc():
p = subprocess.Popen("wmic product where \"Name like 'Microsoft .Net%'\" get Name, Version", stdout=subprocess.PIPE, stderr=subprocess.PIPE)
out, err = p.communicate()
print out
print err
with open('myOutputFile.txt', 'w') as f:
f.write(out) #Write the output to a file
myFunc()
Hope it helps!
|
Python itertools.product() get item index
Question: I have a given tuple `my_tuple` and I know it is in the return object of
itertools.product(). How could I find the index of `my_tuple` without
iterating over the itertools.product() object?
import itertools
permutations = itertools.product(my_sorted_list, repeat = perm_length)
Expected output similar of `any_list.index(interesting_pattern)`
**Edit** Note that I cannot use list() on the object because of memory
constraints
Using Python 2.7
Answer: You don't want to use `itertools.product` in this case. If you only want the
index, than you should calculate it with math.
Like others said before, this one is slow and needs a lot of memory:
import itertools
print list(itertools.product([0, 2, 3, 5], repeat=3)).index((3, 0, 2))
Much better is:
def product_index(sorted_list, repeat, interesting_pattern):
result = 0
for index, number in enumerate(interesting_pattern):
result += sorted_list.index(number) * len(sorted_list)**(repeat - 1 - index)
return result
print product_index([0, 2, 3, 5], 3, (3, 0, 2))
### Explanation:
Just look at the output of `list(itertools([0, 2, 3, 5], repeat=3))`:
[(0, 0, 0), (0, 0, 2), (0, 0, 3), (0, 0, 5), (0, 2, 0), (0, 2, 2), (0, 2, 3),
(0, 2, 5), (0, 3, 0), (0, 3, 2), (0, 3, 3), (0, 3, 5), (0, 5, 0), (0, 5, 2),
(0, 5, 3), (0, 5, 5), (2, 0, 0), (2, 0, 2), (2, 0, 3), (2, 0, 5), (2, 2, 0),
(2, 2, 2), (2, 2, 3), (2, 2, 5), (2, 3, 0), (2, 3, 2), (2, 3, 3), (2, 3, 5),
(2, 5, 0), (2, 5, 2), (2, 5, 3), (2, 5, 5), (3, 0, 0), (3, 0, 2), (3, 0, 3),
(3, 0, 5), (3, 2, 0), (3, 2, 2), (3, 2, 3), (3, 2, 5), ...]
Since the input list is sorted, the generated tuples are also sorted. At first
`itertools.product` generates all tuples of length `3`, that start with `0`.
Then there are all tuples of length `3` that start with `2`. And so on.
So the algorithm goes through each element of `interesting_pattern` and
determines, how many of these tuples start with a number smaller.
So for `interesting_pattern = (3, 0, 2)` we have:
* How many tuples of length `3` are there, where the first element is smaller than `3`? For the first element there are 2 possibilities (`0` and `2`) and all the other elements can be everything (4 possibilities). So there are `2*4*4 = 2*4^2 = 32`. Now we have the first digit 3, and only have to look at the subtuple `(0, 2)`.
* How many tuples of length `2` are there, where the first element is smaller than `0`? There is no possibility for the first element, but 4 possibilities for the second element, so `0*4 = 0*4^1 = 0`.
* And at last. How many tuples of length `1` are there, where the first element is smaller than `2`? There is 1 possibility for the first element (`0`), so `1 = 1*4^0 = 1`.
In total we get `32 + 0 + 1 = 33`. The index is `33`.
### edit:
This algorithm is probably even faster, since you don't have to compute any
powers.
def product_index2(sorted_list, interesting_pattern):
result = 0
for number in interesting_pattern:
result = result * len(sorted_list) + sorted_list.index(number)
return result
|
array - float64 to array - ndarray
Question: I am new to python, am not aware of data types.
I want the output to be in the form
[[ 0.3120883 ]
[ 0.36910208]
[ 0.99886361]
...,
[-0.10729821]
[ 0.08311962]
[ 1.67302086]]
But currently my output is the form
[-0.13562086 -0.11107482 0.1600553 ..., -0.3161786 -0.23419835
0.45029903]
How to convert it?
Answer: You can
[`numpy.reshape`](http://docs.scipy.org/doc/numpy/reference/generated/numpy.reshape.html)
it to `(-1,1)` to get the result in the form you want. Example -
narray = narray.reshape((-1,1))
Demo -
In [19]: import numpy as np
In [20]: narray = np.arange(10)
In [21]: narray
Out[21]: array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
In [22]: narray.reshape((-1,1))
Out[22]:
array([[0],
[1],
[2],
[3],
[4],
[5],
[6],
[7],
[8],
[9]])
Basically what you are doing is to change the shape of the array from
something like - `(n,)` to `(n,1)` , you do this by using
[`reshape()`](http://docs.scipy.org/doc/numpy/reference/generated/numpy.reshape.html#numpy.reshape)
, in it you can pass `-1` as one of the arguments. As given in documentation -
> `newshape` : int or tuple of ints
>
> The new shape should be compatible with the original shape. If an integer,
> then the result will be a 1-D array of that length. **One shape dimension
> can be -1. In this case, the value is inferred from the length of the array
> and remaining dimensions.**
|
concatenating python strings in a loop
Question: I am using enums and string.join() method to form a help string in Python:
I have the following code segment:
from enum import Enum
class Estimators(Enum):
rsac = 1
msac = 2
Now, I create a help string as follows:
est_help = 'Valid options are: [' + (str(i.name) + ', ' for i in Estimators) + ']'
This throws a TypeError exception as:
TypeError: cannot concatenate 'str' and 'generator' objects
I was wondering what I am doing wrong. The `i.name` is of string type.
Answer: The error message tells you what you are doing wrong - attempting to
concatenate a string and a generator. What you want to do is to make a list
using list comprehension based on the generator, then use that
est_help = 'Valid options are: [{}]'.format( ', '.join( i.name for i in Estimators))
Let's decompose this into individual steps:
1. Create the list `[rsac,msac]`: `est_list = [str(i.name) for i in Estimators]`
2. Create a string with the list elements separated by a comma `'rsac, msac'`: `est_str = ', '.join( est_list )`
3. Insert the string into your text template: `est_help = 'Valid options are: [{}]'.format( est_str )`, and get the resulting string `Valid options are: [rsac, msac]'`
**edit: modified code incorporating suggestions from comments**
est_help = 'Valid options are: [{}]'.format( ', '.join( i.name for i in Estimators ) )
|
Moving Mouse in Python on VM
Question: I am trying to move my mouse using this simple code.
import win32api, win32con
def click(x,y):
win32api.SetCursorPos((x,y))
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTDOWN,x,y,0,0)
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTUP,x,y,0,0)
click(10,10)
My machine is running MacOS, and I run a Virtual Machine on my computer with
windows 7. When I run this code on my Virtual Machine, it doesnt move the
actual mouse, but rather uses a "ghost mouse" to make the click. When I try to
use this code to make the mouse move on a windows desktop machine, you can see
the cursor moving (unlike on my VM).
Are there any ideas to making the actual mouse cursor move on my virtual
machine through python?
Thanks!
Answer: From what I can tell, I don't really believe it's possible. For all the VM
knows, the host doesn't really even exist (for the most part). One major thing
VMs do is sandbox the client from the host. (See
[security.SE](http://security.stackexchange.com/questions/9011/does-a-virtual-
machine-stop-malware-from-doing-harm)).
The other thing is, that would be a massive security issue. If I had access to
your machine from the VM, then I could ostensibly click through and install
malware.
Now for the catch: You probably can.
VMS can communicate to their host through the network, so if you had a server
listening on the host for the communication, and the host moves the cursor
after reading the comms, then yes. Note that this method requires explicitly
setting up the host to listen to the client. No method I am aware of allows
the VM to directly interact with the host without the host "listening".
|
Python - plot a NxN matrix as a gradient colors grid
Question: I want to visualize the correlation between columns that I get with
`datafrome.corr()` method.
The result looks like:
[](http://i.stack.imgur.com/MRqmL.png)
What I am trying to do here is to draw that matrix with gradient colors based
on the values of the data frame.
Something like (Just an example from the web):
[](http://i.stack.imgur.com/48dVc.png)
Answer: If you can import your data into numpy here is a simple solution using
matplotlib and should produce a heatmap similar to what you posted. You will
just need to replace the dummy data with your data.
import numpy as np
import matplotlib.pyplot as plt
# Generate some test data
data = np.arange(100).reshape((10,10))
plt.title('Actual Function')
heatmap = plt.pcolor(data)
plt.show()
**Edit:** Here is a bit fancier version with your x and y axis labels. I chose
to put them into two lists so that you could change each one independently.
import numpy as np
import matplotlib.pyplot as plt
# Generate some test data
data = np.arange(100).reshape((10,10))
xlabels = ['capacity', 'failure_rate', 'id', 'margin', 'price', 'prod_cost', 'product_type', 'quality', 'warranty', 'market_share', 'attractiveness']
ylabels = ['capacity', 'failure_rate', 'id', 'margin', 'price', 'prod_cost', 'product_type', 'quality', 'warranty', 'market_share', 'attractiveness']
fig, ax = plt.subplots()
ax.set_xticks(np.arange(data.shape[1]) + 0.5, minor=False)
ax.set_yticks(np.arange(data.shape[0]) + 0.5, minor=False)
ax.xaxis.tick_top()
plt.xticks(rotation=90)
ax.set_xticklabels(xlabels, minor=False)
ax.set_yticklabels(ylabels, minor=False)
heatmap = ax.pcolor(data)
ax = plt.gca()
for t in ax.xaxis.get_major_ticks():
t.tick1On = False
t.tick2On = False
for t in ax.yaxis.get_major_ticks():
t.tick1On = False
t.tick2On = False
plt.show()
|
capturing only certain characters in regular expression by python
Question: I'm trying to create pattern that detects certain strings. Basically, the
purpose is if detect 'ABCDEF' in a string then return "true". but between
'ABC' and 'DEF', there would be (L+count) or (number) or not like examples
below. BTW all examples below return "true". It would be really appreciate if
some one can advise how to ignore those combo of number and characters between
"ABC" and "DEF"?
ABC(L30)(345)DEF, ABC(L2)(45)DEF, ABCDEF, ABC(L10)DEF, ABC(2)DEF
Answer: Regex compose thinking path:
* Start with ABC
* Ends with DEF
* Either (L[0-9]+) or ([0-9]+) or empty
>
> #!/usr/bin/python
> import re
> r=re.compile("ABC(\(L[0-9]+\)|\([0-9]+\)|)*DEF");
> lines = [
> "ABC(L30)(345)DEF",
> "ABC(L2)(45)DEF",
> "ABC(L30)DEF",
> "ABC(345)DEF",
> "ABCDEF",
> "ABCxyzDEF",
> "ABC(L)DEF",
> "ABC(A)DEF",
> "ABC()DEF",
> ]
> for str in lines:
> if r.match(str):
> print " match : %s" % str
> else:
> print "not match : %s" % str
>
Output:
>
> match : ABC(L30)(345)DEF
> match : ABC(L2)(45)DEF
> match : ABC(L30)DEF
> match : ABC(345)DEF
> match : ABCDEF
> not match : ABCxyzDEF
> not match : ABC(L)DEF
> not match : ABC(A)DEF
> not match : ABC()DEF
>
|
Error during pip install ldavis
Question: I have been attempting to install a Python package by the name of 'pyLDAvis'
from cmd with no success since over a day now! I ran the following command
from cmd -
pip install pyldavis
I have already installed Microsoft Visual C++ 2010. Further, I have also
performed the steps mentioned at <http://stackoverflow.com/a/26513378/3228300>
(Installing Win SDK 7.1, change the redistributable pkgs and create a
vcvars64.bat file). Sadly, I do not know how to proceed further. I am pasting
the ending snippet of code that is thrown back at me when the installation
stops below -
c:\users\ABC\anaconda3\lib\site-packages\numpy\core\include\num
py\npy_1_7_deprecated_api.h(12) : Warning Msg: Using deprecated NumPy API, disab
le it by #defining NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\Bin\amd64\link.exe /D
LL /nologo /INCREMENTAL:NO "/LIBPATH:C:\Users\ABC\Anaconda3\libs" "
/LIBPATH:C:\Users\ABC\Anaconda3\PCbuild\amd64" /EXPORT:PyInit___sub
sample build\temp.win-amd64-3.4\Release\skbio/stats/__subsample.obj /OUT:build\l
ib.win-amd64-3.4\skbio\stats\__subsample.pyd /IMPLIB:build\temp.win-amd64-3.4\Re
lease\skbio/stats\__subsample.lib /MANIFESTFILE:build\temp.win-amd64-3.4\Release
\skbio/stats\__subsample.pyd.manifest
__subsample.obj : warning LNK4197: export 'PyInit___subsample' specified mul
tiple times; using first specification
Creating library build\temp.win-amd64-3.4\Release\skbio/stats\__subsample
.lib and object build\temp.win-amd64-3.4\Release\skbio/stats\__subsample.exp
building 'skbio.alignment._ssw_wrapper' extension
creating build\temp.win-amd64-3.4\Release\skbio\alignment
creating build\temp.win-amd64-3.4\Release\skbio\alignment\_lib
C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\Bin\amd64\cl.exe /c /
nologo /Ox /MD /W3 /GS- /DNDEBUG "-IC:\Users\ABC\Anaconda3\lib\site
-packages\numpy\core\include" "-IC:\Users\ABC\Anaconda3\include" "-
IC:\Users\ABC\Anaconda3\include" /Tcskbio/alignment/_ssw_wrapper.c
/Fobuild\temp.win-amd64-3.4\Release\skbio/alignment/_ssw_wrapper.obj -Wno-error=
declaration-after-statement
cl : Command line error D8021 : invalid numeric argument '/Wno-error=declara
tion-after-statement'
error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio 10.0\\VC\\B
in\\amd64\\cl.exe' failed with exit status 2
----------------------------------------
Command ""C:\Users\ABC\Anaconda3\python.exe" -c "import setuptools,
tokenize;__file__='C:\\Users\\ABC1\\AppData\\Local\\Temp\\pip-build-cp30pok
9\\scikit-bio\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).
read().replace('\r\n', '\n'), __file__, 'exec'))" install --record C:\Users\ABC1\AppData\Local\Temp\pip-hto4uniu-record\install-record.txt --single-version-
externally-managed --compile" failed with error code 1 in C:\Users\ABC1\AppD
ata\Local\Temp\pip-build-cp30pok9\scikit-bio
Any suggestions helping me out of this situation are welcome. P.S. I run
Python 3.4 on a Windows 7 desktop (6 GB ram).
Answer: pyldavis does not work for windows machines because sci-kit bio package is not
compiled for windows binaries... it seems this will be available mid 2016.
You will need to use Linux or OSX to get pyldavis working.
|
How to verify if indexes of letter from word matches index of letter from words from list in python?
Question: I have multiple functions which return a list of words (each function contains
words that start with the same letter):
def get_a():
# ..some code
return words_a # words_a contain a list with some words that begin with a
... # and so on
def get_y():
# ..some code
return words_y # words_y contain a list with some words that begin with y
Output example: `['yahoo', 'yep', 'yellow']`
Now, I have a random word ( I know its `len` and only some letters which are
located at specific indexes - I also know these )
Supposing that I have the following `partial_word` (I have `0` instead of the
empty spaces):
`partial_word = 00LL0W`
What is the best way of getting a list with words(from all my functions) that
will satisfy the following condition:
* all known index letters(in my example `L(position2) L(position3) W(position5`) from the `partial_word` will match at the exact same positions the letters from the words from my functions ?
* another important detail is that each function returns a list with 3-4k words.
Answer: You may make use of the build-in regular expression library
import re
partial_word = '00LL0W'
pattern = '^' + partial_word + '$'
pattern = pattern.replace('0', '\w')
example_word = 'YELLOW'
m = re.match(pattern, example_word)
print m.group(0)
|
Create a list of lists / matrices from a text file in Python 3.4
Question: I need to create a set of matrices from the file below, the lines/rows with
the same value of Z will go in a matrix together.
Below is a shortened version of my txt file:
X Y Z
-1 10 0
1 20 5
2 15 10
2 50 10
2 90 10
3 15 11
4 50 11
5 90 11
6 13 14
7 50 14
8 70 14
8 95 14
8 75 14
So for example my first matrix will be
[-1, 10, 0],
my second one will be
[1, 20, 5],
my third will be
([2, 15, 10],
[2, 50, 10],
[2, 90, 10]) etc
I've looked at a few questions related to this but nothing seems to be quite
right.
I started by making each column an array. I was thinking a for loop might work
well. So far I have
f = open("data.txt", "r")
header1 = f.readline()
for line in f:
line = line.strip()
columns = line.split()
x = columns[0]
y = columns[1]
z = columns[2]
i = line in f
z.old = line(i-1,4)
i=1
for line in f:
f.readline(i)
if z(0) == [i,3]:
line(i) = matrix[i,:]
else z(0) != [i,3]:
store line(i) as M
continue
i = i+1
however, I'm getting 'invalid syntax' for line,
else z(0) != line(4):
By this else clause, I mean that `if z(0)/(z initial) is not equal to line(4)`
then this line will then get stored as the first line of the next matrix we
will check under this code.
However, I'm not sure how well this would work.
Any help would be greatly appreciated!
Answer: The following should work for your data, it assumes the columns in your text
file are tab delimited:
import csv
import operator
with open('input.txt', 'rb') as f_input:
csv_input = csv.reader(f_input, delimiter='\t')
headers = next(csv_input)
row_number = 1
for k, g in itertools.groupby(csv_input, key=operator.itemgetter(0)):
row = []
for entry in g:
entry = [float(e) for e in entry]
row.append([row_number] + entry)
row_number += 1
print row
This would print the following output:
[[1, -1, 10, 0]]
[[2, 1, 20, 5]]
[[3, 2, 15, 10], [4, 2, 50, 10], [5, 2, 90, 10]]
[[6, 3, 15, 11]]
[[7, 4, 50, 11]]
[[8, 5, 90, 11]]
[[9, 6, 13, 14]]
[[10, 7, 50, 14]]
[[11, 8, 70, 14], [12, 8, 95, 14], [13, 8, 75, 14]]
If your CSV file is exactly as you have it shown, i.e. with spaces separating
the columns, then you will need to change the `csv.reader` line as follows:
csv_input = csv.reader(f_input, delimiter=' ', skipinitialspace=True)
|
search for pattern in string
Question: I need to find a pattern ATG[any number of any characters triplets][TGA or TAG
or TGA], where I need only the first ATG, further up to [TGA or TAG or TAA] do
not matter.
And this should be interrupted at [TGA or TAG or TAA]. In string there could
be several such, they do not need to overlap.
For example search on 'ATGcccATGgggTAGgATGtttTAA' should give
'ATGcccATGgggTAG' and 'ATGtttTAA' as a result.
Is there any way to do this in Python?
Answer: This is a job for a regex. (Note that your expected result does not seem to
match your specification; you originally say you want to match up to TGA, TAG
or TGA, but then in the result you match up to TAA. I'll assume the end of the
string is meant to be TGA.)
import re
target = 'ATGcccATGgggTAGgATGtttTGA'
results = re.findall(r'(ATG.*?(?:TAG|TGA|TGA))', target)
# ['ATGcccATGgggTAG', 'ATGtttTGA']
|
Why Python splits read function into multiple syscalls?
Question: I tested this:
strace python -c "fp = open('/dev/urandom', 'rb'); ans = fp.read(65600); fp.close()"
With the following partial output:
read(3, "\211^\250\202P\32\344\262\373\332\241y\226\340\16\16!<\354\250\221\261\331\242\304\375\24\36\253!\345\311"..., 65536) = 65536
read(3, "\7\220-\344\365\245\240\346\241>Z\330\266^Gy\320\275\231\30^\266\364\253\256\263\214\310\345\217\221\300"..., 4096) = 4096
There are two calls for read syscall with different number of requested bytes.
When I repeat the same using dd command,
dd if=/dev/urandom bs=65600 count=1 of=/dev/null
just one read syscall is triggered using the exact number of bytes requested.
read(0, "P.i\246!\356o\10A\307\376\2332\365=\262r`\273\"\370\4\n!\364J\316Q1\346\26\317"..., 65600) = 65600
I have googled this without any possible explanation. Is this related to page
size or any Python memory management?
Why does this happen?
Answer: I did some research on exactly why this happens.
Note: I did my tests with Python 3.5. Python 2 has a different I/O system with
the same quirk for a similar reason, but this was easier to understand with
the new IO system in Python 3.
As it turns out, this is due to Python's BufferedReader, not anything about
the actual system calls.
You can try this code:
fp = open('/dev/urandom', 'rb')
fp = fp.detach()
ans = fp.read(65600)
fp.close()
If you try to strace this code, you will find:
read(3, "]\"\34\277V\21\223$l\361\234\16:\306V\323\266M\215\331\3bdU\265C\213\227\225pWV"..., 65600) = 65600
Our original file object was a BufferedReader:
>>> open("/dev/urandom", "rb")
<_io.BufferedReader name='/dev/urandom'>
If we call `detach()` on this, then we throw away the BufferedReader portion
and just get the FileIO, which is what talks to the kernel. At this layer,
it'll read everything at once.
So the behavior that we're looking for is in BufferedReader. We can look in
`Modules/_io/bufferedio.c` in the Python source, specifically the function
`_io__Buffered_read_impl`. In our case, where the file has not yet been read
from until this point, we dispatch to `_bufferedreader_read_generic`.
Now, this is where the quirk we see comes from:
while (remaining > 0) {
/* We want to read a whole block at the end into buffer.
If we had readv() we could do this in one pass. */
Py_ssize_t r = MINUS_LAST_BLOCK(self, remaining);
if (r == 0)
break;
r = _bufferedreader_raw_read(self, out + written, r);
Essentially, this will read as many full "blocks" as possible directly into
the output buffer. The block size is based on the parameter passed to the
`BufferedReader` constructor, which has a default selected by a few
parameters:
* Binary files are buffered in fixed-size chunks; the size of the buffer
is chosen using a heuristic trying to determine the underlying device's
"block size" and falling back on `io.DEFAULT_BUFFER_SIZE`.
On many systems, the buffer will typically be 4096 or 8192 bytes long.
So this code will read as much as possible without needing to start filling
its buffer. This will be 65536 bytes in this case, because it's the largest
multiple of 4096 bytes less than or equal to 65600. By doing this, it can read
the data directly into the output and avoid filling up and emptying its own
buffer, which would be slower.
Once it's done with that, there might be a bit more to read. In our case,
`65600 - 65536 == 64`, so it needs to read at least 64 more bytes. But yet it
reads 4096! What gives? Well, the key here is that the point of a
BufferedReader is to minimize the number of kernel reads we actually have to
do, as each read has significant overhead in and of itself. So it simply reads
another block to fill its buffer (so 4096 bytes) and gives you the first 64 of
these.
Hopefully, that makes sense in terms of explaining why it happens like this.
As a demonstration, we could try this program:
import _io
fp = _io.BufferedReader(_io.FileIO("/dev/urandom", "rb"), 30000)
ans = fp.read(65600)
fp.close()
With this, strace tells us:
read(3, "\357\202{u'\364\6R\fr\20\f~\254\372\3705\2\332JF\n\210\341\2s\365]\270\r\306B"..., 60000) = 60000
read(3, "\266_ \323\346\302}\32\334Yl\ry\215\326\222\363O\303\367\353\340\303\234\0\370Y_\3232\21\36"..., 30000) = 30000
Sure enough, this follows the same pattern: as many blocks as possible, and
then one more.
`dd`, in a quest for high efficiency of copying lots and lots of data, would
try to read up to a much larger amount at once, which is why it only uses one
read. Try it with a larger set of data, and I suspect you may find multiple
calls to read.
TL;DR: the BufferedReader reads as many full blocks as possible (64 * 4096)
and then one extra block of 4096 to fill its buffer.
EDIT:
The easy way to change the buffer size, as @fcatho pointed out, is to change
the `buffering` argument on `open`:
>
> open(name[, mode[, buffering]])
>
>
> ( ... )
>
> The optional buffering argument specifies the file’s desired buffer size: 0
> means unbuffered, 1 means line buffered, any other positive value means use
> a buffer of (approximately) that size (in bytes). A negative buffering means
> to use the system default, which is usually line buffered for tty devices
> and fully buffered for other files. If omitted, the system default is used.
This works on both [Python
2](https://docs.python.org/2/library/functions.html#open) and [Python
3](https://docs.python.org/3/library/functions.html#open).
|
Replace sequences between files using Biopython
Question: I have two protein sequences FASTA files:
nsp.fasta --> original file
wsp.fasta --> output file from a signal peptide predictor tool, which returned
the proteins in nsp.fasta with the signal stripped.
For example:
record in nsp.fasta:
>gi|564250271|ref|XP_006264203.1| PREDICTED: apolipoprotein D [Alligator mississippiensis]
MRGMLALLAALLGLLGLVEGQTFHMGQCPNPPVQEDFDPSKYLGKWYEIEKLPSGFEQER
CVQANYSLKANGKIKVLTKMVRSAQHLTCLQHRMMLLVSSPVMPASPYWVVATDYENYAL
VYSCTSFFWLFHVDYAWIRSRTPQLHPETVEHLKSVLRSYRIQTGMMLPTDQMNCPSDM
record in wsp.fasta:
>gi|564250271|ref|XP|006264203.1| PREDICTED: apolipoprotein D [Alligator mississippiensis]; MatureChain: 21-179
QTFHMGQCPNPPVQEDFDPSKYLGKWYEIEKLPSGFEQERCVQANYSLKANGKIKVLTKM
VRSAQHLTCLQHRMMLLVSSPVMPASPYWVVATDYENYALVYSCTSFFWLFHVDYAWIRS
RTPQLHPETVEHLKSVLRSYRIQTGMMLPTDQMNCPSDM
However, not all the proteins in nsp.fasta contained a signal peptide, so
wsp.fasta is a subset of the proteins in nsp.fasta that contains the signal.
What I need is a unique file that contains all the protein records, both
proteins with no signal peptide found and the mature chains with the signal
peptide stripped.
I have tried the following:
from Bio import SeqIO
file1 = SeqIO.parse(r"c:\Users\Sergio\Desktop\nsp.fasta", "fasta")
file2 = SeqIO.parse(r"c:\Users\Sergio\Desktop\wsp.fasta", "fasta")
for seq1 in file1:
for seq2 in file2:
if seq2.id == seq1.id:
seq1.seq = seq2.seq
SeqIO.write(seq1, r"c:\Users\Sergio\Desktop\nuevsp.fasta", "fasta")
But there's no output at all. I have tried putting the SeqIO.write out of the
loops, and it returns a blank file. What am I doing wrong? There already exist
any method to merge two files or to replace sequences in one file with
sequences in other file?
Thank you in advance!!
Sergio
Edited code, I added an elif clause in an attempt to also add the records in
nsp.fasta that doesn't match wsp.fasta, but it doesn't work:
to_write = []
for seq1 in SeqIO.parse(r"c:\Users\Sergio\Desktop\nsp.txt", "fasta"):
for seq2 in SeqIO.parse(r"c:\Users\Sergio\Desktop\wsp.txt", "fasta"):
if seq1.id == seq2.id:
seq1.seq = seq2.seq
to_write.append(seq1)
elif seq1.id != seq2.id:
to_write.append(seq1)
SeqIO.write(to_write, r"c:\Users\Sergio\Desktop\nuevsp.txt", "fasta")
Answer: As you have written it, every time you write a new sequence, you're
overwriting the previous one. Try storing your records in a list and then
writing out the list when the loop is completed.
to_write = []
for seq1 in SeqIO.parse(r"c:\Users\Sergio\Desktop\nsp.fasta", "fasta"):
for seq2 in SeqIO.parse(r"c:\Users\Sergio\Desktop\wsp.fasta", "fasta"):
if seq2.id == seq1.id:
seq1.seq = seq2.seq
to_write.append(seq1)
SeqIO.write(to_write, r"c:\Users\Sergio\Desktop\nuevsp.fasta", "fasta")
Edit to suggest another approach using list comprehensions:
ids_to_save = [x.id for x in SeqIO.parse(r"c:\Users\Sergio\Desktop\nsp.fasta", "fasta")]
records_to_save = [x for x in SeqIO.parse(r"c:\Users\Sergio\Desktop\wsp.fasta", "fasta") if (x.id in ids_to_save)]
SeqIO.write(records_to_save, r"c:\Users\Sergio\Desktop\nuevsp.fasta", "fasta")
Edit to address the "add the records in nsp.fasta that doesn't match
wsp.fasta" need - general approach, not necessarily exact code:
ids_not_wanted = [x.id for x in SeqIO.parse(r"c:\Users\Sergio\Desktop\wsp.fasta", "fasta")]
records_to_save_2 = [x for x in SeqIO.parse(r"c:\Users\Sergio\Desktop\wsp.fasta", "fasta") if (x.id not in ids_not_wanted)]
records_to_save.append(records_to_save_2)
# If duplicate records are a problem, eliminate them using "set"
records_to_save = list(set(records_to_save))
SeqIO.write(records_to_save, r"c:\Users\Sergio\Desktop\nuevsp.fasta", "fasta")
|
How do I add a 'google' module for protocol buffers in Python in Visual Studio 2013?
Question: I'm following the tutorial at <https://developers.google.com/protocol-
buffers/docs/pythontutorial> .
I've managed to create the `addressbook_pb2.py` from the proto file. I added
`addressbook_pb2.py` to my project, and when I do `import addressbook_pb2` the
.py file pops up as I type the name, so I know the program recognizes it.
When I try to run the program, which consists of only the line `import
addressbook_pb2`, I receive the error `No module named 'google'`. I am
extremely new to Python, how would I go about fixing this error? I am running
Python 3.4 in Visual Studio 2013
The error is caused at each `importing google.protobuf` line in my
'addressbook_pb2.py' file
# Generated by the protocol buffer compiler. DO NOT EDIT!
# source: addressbook.proto
import sys
_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
from google.protobuf import descriptor as _descriptor
from google.protobuf import message as _message
from google.protobuf import reflection as _reflection
from google.protobuf import symbol_database as _symbol_database
from google.protobuf import descriptor_pb2
Answer: This problem is often caused by having multiple Pythons installed. Solutions
to this is explained [here](http://stackoverflow.com/questions/21196648/how-
can-i-use-protocol-buffers-for-python-on-windows) and
[here](http://stackoverflow.com/questions/31308812/no-module-named-google-
protobuf).
|
Python regex: Remove a pattern at the end of string
Question: Input: `blah.(2/2)`
Desired Output: `blah`
Input can be "blah.(n/n)" where n can be any single digit number.
How do I use regex to achieve "blah"? This is the regex I currently have which
doesn't work:
m = re.sub('[.[0-9] /\ [0-9]]{6}$', '', m)
Answer: You need to use regex `\.\(\d/\d\)$`
>>> import re
>>> str = "blah.(2/2)"
>>> re.sub(r'\.\(\d/\d\)$', '',str)
'blah'
**[Regex explanation here](https://regex101.com/r/uB8vX3/2)**
|
Python tkinter update_idletasks is blanking the window
Question: [This has been fairly significantly edited in the light of comments to the
original post, and to make the context - 2 modules - clearer and to summarise
what I think is the key underlying issue. The code is also updated. I have a
working version but am not at all sure its done the right way.] (Disclaimer
... Im learning Tkinter as I go along!)
Im attempting to display a progress bar while an app is running (eg walking a
music library folder tree but that doesnt matter here).
I'd like to implement this as a class in a separate module from the main app
so I can use it elsewhere (also the app itself is actually in 2 modules).
For that reason, and also because I don't want to upset the app's main window
design Id like the progress bar to appear in a separate window.
I've tried this two ways ... my own crudely drawn progress bar using a text
widget, and - once I discovered it - ttk.Progressbar. Im now focusing on using
ttk.Progressbar.
Note however I had essentially the same problem with either approach, which is
getting the contents of the progress window to display properly without
preventing control reverting back to the calling module.
My class for this (ProgressBar) has methods to start, update, and stop the
progress bar. As I understand it there are three ways to force refreshing of
the status window in the class methods. All three seem to have drawbacks.
* root.master.mainloop() keeps control in the progress window and the app stops executing. This basically defeats the purpose.
* root.master.update_idletasks() gives control back to the calling app but the status window is blanked out. Also defeats the purpose, for a different reason.
* root.master.update() seems to work perfectly, the status window is updated with visible contents and control goes back to the calling app. HOWEVER Ive read in several places this is a dangerous method to use.
So the basic questions are - What is the correct way to force the window to
update (eg the Set method); and why is update_idletasks() blanking the
progress window.
I believe the following code reflects the suggestions made but I have adapted
it to reflect the intended import class.
# dummy application importing the StatusBar class.
# this reflects app is itslef using tkinter
from ProgressBar12 import ProgressBar
import tkinter as Tk
import time
import os
def RunAppProcess():
print('App running')
Bar = ProgressBar(tkroot) # '' arg to have ProgressBar create its tkroot
Bar.start('Progress...', 0) # >0 determinate (works) / 0 for indeterminate (doesnt!)
print('starting process')
# this simulates some process, (eg for root, dirs, files = os.walk(lib))
for k in range(10):
Bar.step(5) # (should be) optional for indeterminate
time.sleep(.2)
Bar.stop('done') # '' => kill the window; or 'message' to display in window
def EndAppProcess():
tkroot.withdraw()
tkroot.destroy()
# Application init code, the application is using tkinter
# (should probably be in an init procedure etc, but this will serve)
tkroot = Tk.Tk()
tkroot.title("An Application")
tkroot.geometry("100x100")
tkroot.configure(bg='khaki1')
# a 2 button mini window: [Start] and [Quit]
Tk.Button(tkroot, text='Start', bg='orange', command=RunAppProcess).grid(sticky=Tk.W)
Tk.Button(tkroot, text="Quit", bg="orange", command=EndAppProcess).grid(sticky=Tk.W)
tkroot.mainloop()
ProgressBar Module
# determinate mode
import tkinter as Tk
import tkinter.font as TkF
from tkinter import ttk
import time
# print statements are for tracing execution
# changes from the sample code previsouly given reflect:
# - suggestions made in the answer and in comments
# - to reflect the actual usage with the class imported into a calling module rather than single module solution
# - consistent terminology (progress not status)
# - having the class handle either determinate or indeterminate progress bar
class ProgressBar():
def __init__(self, root):
print('progress bar instance init')
if root == '':
root = tkInit()
self.master=Tk.Toplevel(root)
# Tk.Button(root, text="Quit all", bg="orange", command=root.quit).grid() A bit rude to mod the callers window
self.customFont2 = TkF.Font(family="Calibri", size=12, weight='bold')
self.customFont5 = TkF.Font(family="Cambria", size=16, weight='bold')
self.master.config(background='ivory2')
self.create_widgets()
self.N = 0
self.maxN = 100 # default for %
def create_widgets(self):
self.msg = Tk.Label(self.master, text='None', bg='ivory2', fg='blue4') #, font=self.customFont2)
self.msg.grid(row=0, column=0, sticky=Tk.W)
self.bar = ttk.Progressbar(self.master, length=300, mode='indeterminate')
self.bar.grid(row=1, column=0, sticky=Tk.W)
#self.btn_abort = Tk.Button(self.master, text=' Abort ', command=self.abort, font=self.customFont2, fg='maroon')
#self.btn_abort.grid(row=2,column=0, sticky=Tk.W)
#self.master.rowconfigure(2, pad=3)
print('progress bar widgets done')
def start(self, msg, maxN):
if maxN <= 0:
#indeterminate
self.msg.configure(text=msg)
self.bar.configure(mode='indeterminate')
self.maxN = 0
self.bar.start()
self.master.update()
else: # determinate
self.msg.configure(text=msg)
self.bar.configure(mode='determinate')
self.maxN = maxN
self.N = 0
self.bar['maximum'] = maxN
self.bar['value'] = 0
def step(self, K):
#if self.maxN == 0: return # or raise error?
self.N = min(self.maxN, K+self.N)
self.bar['value'] = self.N
self.master.update() # see set(..)
def set(self, K):
#if self.maxN == 0: return
self.N = min(self.maxN, K)
self.bar['value'] = self.N
#self.master.mainloop() # <<< calling module does not regain control. Pointless.
#self.master.update_idletasks # <<< works, EXCEPT statusbar window is blank! Also pointless. But calling module regains control
self.master.update() # <<< works in all regards, BUT I've read this is dangerous.
def stop(self, msg):
print('progress bar stopping')
self.msg.configure(text=msg)
if self.maxN <= 0:
self.bar.stop()
else:
self.bar['value'] = self.maxN
#self.bar.stop()
if msg == '':
self.master.destroy()
else: self.master.update()
def abort(self):
# eventually will raise an error to the calling routine to stop the process
self.master.destroy()
def tkInit():
print('progress bar tk init')
tkroot = Tk.Tk()
tkroot.title("Progress Bar")
tkroot.geometry("250x50")
tkroot.configure(bg='grey77')
tkroot.withdraw()
return tkroot
if (__name__ == '__main__'):
print('start progress bar')
tkroot = tkInit()
tkroot.configure(bg='ivory2')
Bar = ProgressBar(tkroot)
Bar.start('Demo', 10)
for k in range(11):
Bar.set(k)
time.sleep(.2)
Bar.stop('done, you can close me')
else:
# called from another module
print('progress bar module init. (nothing) done.')
This is based on the first of the solutions in the answer; as an alternative I
will try the second using after() .... I first have to understand exactly what
that does.
Answer: First, you don't call mainloop() anywhere. The following code displays a
moving progress bar until you hit the abort button. The for() loop in your
code above serves no purpose as it does nothing except stop program execuption
for 0.3*20 seconds. If you want to update the progress bar yourself, then see
the 2nd example and how it uses "after" to call an update function until the
progress bar completes. And note that everything associated with it is
contained in the class, which is one of the reasons you would use a class. You
could also call the update function from outside the class, but the update
function would still be in the same class that created the progress bar.
import Tkinter as Tk
import tkFont as TkF
import ttk
import time
class StatusBar():
def __init__(self, root):
self.master=Tk.Toplevel(root)
Tk.Button(root, text="Quit all", bg="orange", command=root.quit).grid()
self.customFont2 = TkF.Font(family="Calibri", size=12, weight='bold')
self.customFont5 = TkF.Font(family="Cambria", size=16, weight='bold')
self.master.config(background='ivory2')
self.ctr=0
self.create_widgets()
def create_widgets(self):
self.msg = Tk.Label(self.master, text='None', bg='ivory2', fg='blue4',
font=self.customFont2, width=5)
self.msg.grid(row=0, column=0, sticky=Tk.W)
self.bar = ttk.Progressbar(self.master, length=300, mode='indeterminate')
self.bar.grid(row=1, column=0, sticky=Tk.W)
self.btn_abort = Tk.Button(self.master, text=' Abort ', command=self.abort, font=self.customFont2, fg='maroon')
self.btn_abort.grid(row=2,column=0, sticky=Tk.W)
self.master.rowconfigure(2, pad=3)
print('widgets done')
def Start(self, msg):
self.msg.configure(text=msg)
self.bar.start()
def Stop(self, msg):
self.msg.configure(text=msg)
self.bar.stop()
def abort(self):
# eventually will raise an error to the calling routine to stop the process
self.master.destroy()
if (__name__ == '__main__'):
print('start')
tkroot = Tk.Tk()
tkroot.title("Status Bar")
tkroot.geometry("500x75")
tkroot.configure(bg='ivory2')
Bar = StatusBar(tkroot)
Bar.Start('Demo')
tkroot.mainloop()
Uses after() to update the progress bar
try:
import Tkinter as tk ## Python 2.x
except ImportError:
import tkinter as tk ## Python 3.x
import ttk
class TestProgress():
def __init__(self):
self.root = tk.Tk()
self.root.title('ttk.Progressbar')
self.increment = 0
self.pbar = ttk.Progressbar(self.root, length=300)
self.pbar.pack(padx=5, pady=5)
self.root.after(100, self.advance)
self.root.mainloop()
def advance(self):
# can be a float
self.pbar.step(5)
self.increment += 5
if self.increment < 100:
self.root.after(500, self.advance)
else:
self.root.quit()
TP=TestProgress()
|
How to remove connecting area in fill_between() using Python and MatPlot
Question: I am graphing +-2 standard deviations from the mean on my graph (the green
points). However, I would rather have straight vertical lines on top of each
x-mean, because currently there is a connecting shade area between states that
is misleading. How can I do this? I've tried everything and can't figure it
out. Thanks in advance. (Since I'm new to Stack Overflow I can't post an image
of my graph unfortunately.)
plt.scatter(x= joined.index.values, y = joined.poll_mean, color = "g")
plt.scatter(x= joined.index.values, y = joined.spread,color = joined.color)
plt.fill_between(joined.index,(joined.poll_mean + 2*joined.poll_std).values, (joined.poll_mean - 2*joined.poll_std).values, color='g', alpha = .3)
plt.xticks(joined.index.values, joined.state.values, rotation='vertical')
Answer: Are you trying to do error bars? There is a matplotlib package for that.
An example piece of code to do this (from
[here](http://matplotlib.org/1.2.1/examples/pylab_examples/errorbar_demo.html)):
import numpy as np
import matplotlib.pyplot as plt
# example data
x = np.arange(0.1, 4, 0.5)
y = np.exp(-x)
# example variable error bar values
yerr = 0.1 + 0.2*np.sqrt(x)
xerr = 0.1 + yerr
# First illustrate basic pyplot interface, using defaults where possible.
plt.figure()
plt.errorbar(x, y, xerr=0.2, yerr=0.4)
plt.title("Simplest errorbars, 0.2 in x, 0.4 in y")
Also as a tip, for people to better help you, provide code that can reproduce
your problem in full.
|
Combine functions to later use in map
Question: I have a list of items, coming from one object which are of type A, and a
library that operates on object of type B.
I would like to convert A to B, and later call B's function in a pythonic way.
What I have come up with so far:
def convert_A_to_B(A):
return B(A.something, A.something_else)
def doStuff(a_list):
converted_to_b = list(map(convert_A_to_B, a_list)
return list(map(B.function, converted_to_b))
I could create a lambda to combine these functions, but I feel like there
should be an easier way. Something like:
return list(map(combine(convert_A_to_B, B.function)))
Answer:
from functools import partial, reduce
combine = lambda *xs: partial (reduce, lambda v,x: x(v), xs)
The function is usable such as `combine (A.foo, A.bar) (x)` with is equivalent
to `A.bar(A.foo (x))`.
`combine` will accept a variadic number of functions, and return a new
function that accepts a single value. This value will then be passed through
every previously mentioned function (in chain) until a final result is yield.
* * *
### Sample usage
map (combine (convert_A_to_B, B.function), a_list)
|
incrementing key,value pair inside for loop iterating over dictionary
Question: How can I increment key value pair inside a for loop while iterating over
dictionary in python?
for key,value in mydict.iteritems():
if condition:
#inc key,value
#something to do
I have tried using `next(mydict.iteritems())` and `mydict.iteritems().next()`
but in vain.
I am using python2.7.
EDIT - I know that forloop automatically increments the key,value pair. I want
to manually increment to next pair ( Thus resulting in 2 increments). Also I
can't use continue because I want both the key value pair to be accessible at
same time. So that when I increment, I have the current key value pair as well
as the next. If I use continue, I lose access to current and only get next
key,value pair.
Answer: If you need simultaneous access to two key-value pairs use pairwise from
[itertools recipes](https://docs.python.org/2/library/itertools.html).
from itertools import izip, tee
def pairwise(iterable):
"s -> (s0,s1), (s1,s2), (s2, s3), ..."
a, b = tee(iterable)
next(b, None)
return izip(a, b)
|
Stepsize control of dopri5 integrator
Question: I am trying to solve a simple example with the `dopri5` integrator in
`scipy.integrate.ode`. As the documentation states
> This is an explicit runge-kutta method of order (4)5 due to Dormand & Prince
> (with stepsize control and dense output).
this should work. So here is my example:
import numpy as np
from scipy.integrate import ode
import matplotlib.pyplot as plt
def MassSpring_with_force(t, state):
""" Simple 1DOF dynamics model: m ddx(t) + k x(t) = f(t)"""
# unpack the state vector
x = state[0]
xd = state[1]
# these are our constants
k = 2.5 # Newtons per metre
m = 1.5 # Kilograms
# force
f = force(t)
# compute acceleration xdd
xdd = ( ( -k*x + f) / m )
# return the two state derivatives
return [xd, xdd]
def force(t):
""" Excitation force """
f0 = 1 # force amplitude [N]
freq = 20 # frequency[Hz]
omega = 2 * np.pi *freq # angular frequency [rad/s]
return f0 * np.sin(omega*t)
# Time range
t_start = 0
t_final = 1
# Main program
state_ode_f = ode(MassSpring_with_force)
state_ode_f.set_integrator('dopri5', rtol=1e-6, nsteps=500,
first_step=1e-6, max_step=1e-3)
state2 = [0.0, 0.0] # initial conditions
state_ode_f.set_initial_value(state2, 0)
sol = np.array([[t_start, state2[0], state2[1]]], dtype=float)
print("Time\t\t Timestep\t dx\t\t ddx\t\t state_ode_f.successful()")
while state_ode_f.t < (t_final):
state_ode_f.integrate(t_final, step=True)
sol = np.append(sol, [[state_ode_f.t, state_ode_f.y[0], state_ode_f.y[1]]], axis=0)
print("{0:0.8f}\t {1:0.4e} \t{2:10.3e}\t {3:0.3e}\t {4}".format(
state_ode_f.t, sol[-1, 0]- sol[-2, 0], state_ode_f.y[0], state_ode_f.y[1], state_ode_f.successful()))
The result I get is:
Time Timestep dx ddx state_ode_f.successful()
0.49763822 4.9764e-01 2.475e-03 -8.258e-04 False
0.99863822 5.0100e-01 3.955e-03 -3.754e-03 False
1.00000000 1.3618e-03 3.950e-03 -3.840e-03 False
with a warning:
> c:\python34\lib\site-packages\scipy\integrate_ode.py:1018: UserWarning:
> dopri5: larger nmax is needed self.messages.get(idid, 'Unexpected idid=%s' %
> idid))
The result is incorect. If I run the same code with `vode` integrator, I get
the expected result.
**Edit**
A similar issue is described here: [Using adaptive step sizes with
scipy.integrate.ode](http://stackoverflow.com/questions/12926393/using-
adaptive-step-sizes-with-scipy-integrate-ode)
The suggested solution recommends setting `nsteps=1`, which solves the ODE
correctly and with step-size control. However the integrator returns
`state_ode_f.successful()` as `False`.
Answer: No, there is nothing wrong. You are telling the integrator to perform an
integration step to `t_final` and it performs that step. Internal steps of the
integrator are not reported.
* * *
The sensible thing to do is to give the desired sampling points as input of
the algorithm, set for example `dt=0.1` and use
state_ode_f.integrate( min(state_ode_f.t+dt, t_final) )
There is no single-`step` method in `dopri5`, only `vode` has it defined, see
the source code
<https://github.com/scipy/scipy/blob/v0.14.0/scipy/integrate/_ode.py#L376>,
this could account for the observed differences.
As you found in [Using adaptive step sizes with
scipy.integrate.ode](http://stackoverflow.com/questions/12926393/using-
adaptive-step-sizes-with-scipy-integrate-ode), one can force single-step
behavior by setting the iteration bound `nsteps=1`. This will produce a
warning every time, so one has to suppress these specific warnings to see a
sensible result.
* * *
You should not use a parameter (which is a constant for the integration
interval) for a time-dependent force. Use inside `MassSpring_with_force` the
evaluation `f=force(t)`. Possibly you could pass the function handle of
`force` as parameter.
|
Why does a query invoke a auto-flush in SQLAlchemy?
Question: The code you see above is just a sample but it works to reproduce this error:
sqlalchemy.exc.IntegrityError: (raised as a result of Query-invoked autoflush;
consider using a session.no_autoflush block if this flush is occurring prematurely)
(sqlite3.IntegrityError) NOT NULL constraint failed: X.nn
[SQL: 'INSERT INTO "X" (nn, val) VALUES (?, ?)'] [parameters: (None, 1)]
A mapped instance is still added to a session. The instance wants to know
(which means query on the database) if other instances its own type exists
having the same values. There is a second attribute/column (`_nn`). It is
specified to `NOT NULL`. But by default it is `NULL`.
When the instance (like in the sample) is still added to the session a call to
`query.one()` invoke a auto-flush. This flush create an `INSERT` which tries
to store the instance. This fails because `_nn` is still null and violates the
`NOT NULL` constraint.
That is what I understand currently. But the question is why does it invoke an
auto-flush? Can I block that?
#!/usr/bin/env python3
import os.path
import os
import sqlalchemy as sa
import sqlalchemy.orm as sao
import sqlalchemy.ext.declarative as sad
from sqlalchemy_utils import create_database
_Base = sad.declarative_base()
session = None
class X(_Base):
__tablename__ = 'X'
_oid = sa.Column('oid', sa.Integer, primary_key=True)
_nn = sa.Column('nn', sa.Integer, nullable=False) # NOT NULL!
_val = sa.Column('val', sa.Integer)
def __init__(self, val):
self._val = val
def test(self, session):
q = session.query(X).filter(X._val == self._val)
x = q.one()
print('x={}'.format(x))
dbfile = 'x.db'
def _create_database():
if os.path.exists(dbfile):
os.remove(dbfile)
engine = sa.create_engine('sqlite:///{}'.format(dbfile), echo=True)
create_database(engine.url)
_Base.metadata.create_all(engine)
return sao.sessionmaker(bind=engine)()
if __name__ == '__main__':
session = _create_database()
for val in range(3):
x = X(val)
x._nn = 0
session.add(x)
session.commit()
x = X(1)
session.add(x)
x.test(session)
Of course a solution would be to _not_ add the instance to the session before
`query.one()` was called. This work. But in my real (but to complex for this
question) use-case it isn't a nice solution.
Answer: How to turn off
[autoflush](http://docs.sqlalchemy.org/en/latest/orm/session_api.html?highlight=autoflush#sqlalchemy.orm.session.Session.params.autoflush)
feature:
* Temporary: you can use [no_autoflush](http://docs.sqlalchemy.org/en/latest/orm/session_api.html?highlight=autoflush#sqlalchemy.orm.session.Session.params.autoflush) context manager on snippet where you query the database, i.e. in `X.test` method:
def test(self, session):
with session.no_autoflush:
q = session.query(X).filter(X._val == self._val)
x = q.one()
print('x={}'.format(x))
* Session-wide: just pass `autoflush=False` to your sessionmaker:
return sao.sessionmaker(bind=engine, autoflush=False)()
|
Atom Editor: CMD + R => No Symbols Found
Question: For some reason, Atom doesn't seem to recognize function tags properly with
the default plugin it has mapped to CMD + r. I've tried completely
uninstalling and deleting Atom and it's files and reinstalling to get the
function detection to work properly, but to no avail.
Function detection does not work in C++ or Python, for me. Instead of just
recognizing functions in my Python scripts, it will even list my numpy imports
etc. Somethings pretty wacky with it.
Does anyone know how to deal with this?
[](http://i.stack.imgur.com/VGkU4.png)
Answer: I found the solution from an atom github [issue
comment](https://github.com/atom/symbols-
view/issues/173?#issuecomment-222352841) about the same problem, launching
Atom from command line will make it work.
`cmd+r` maps to `symbols-view:toggle-file-symbols` command, which using
`ctags` to generate language-specific symbols. `ctags` will generate temporary
symbol list file inside your `$TMPDIR` directory , but that environment
variable is not known when Atom launched from Finder.
|
django - ZeroDivisionError when using thumbnail low-level API
Question: I implemented thumbnails for images that are displayed in an inline form, by
creating my custom form ([like
this](http://blog.glaucocustodio.com/2014/04/08/display-thumbnails-in-django-
admin-with-sorl-thumbnail/)).
However, in one case (that I noticed) so far, I get a ZeroDivisionError when
trying to edit a project, and this is apparently caused by [this
line](https://github.com/python-
pillow/Pillow/blob/master/PIL/TiffImagePlugin.py#L482) in TiffImagePlugin,
which is called by get_thumbnail.
Here's the error traceback
[](http://i.stack.imgur.com/L0dmq.png)
[](http://i.stack.imgur.com/7QCtZ.png)
And here's my code (note I'm also using admin-sortable but I don't think
that's related):
from django.contrib.admin.widgets import AdminFileWidget
from django.utils.safestring import mark_safe
from django.forms import ModelForm
from sorl.thumbnail import get_thumbnail
from models import Image
class AdminImageWidget(AdminFileWidget):
def render(self, name, value, attrs=None):
output = []
if value and getattr(value, "url", None):
t = get_thumbnail(value,'80x80')
output.append('<img src="{}">'.format(t.url))
output.append(super(AdminFileWidget, self).render(name, value, attrs))
return mark_safe(u''.join(output))
class ImageForm(ModelForm):
class Meta:
fields = '__all__'
model = Image
widgets = {
'img': AdminImageWidget,
}
class ImageInline(SortableStackedInline):
model = Image
extra = 3
form = ImageForm
class ProjectAdmin(NonSortableParentAdmin):
list_display = ('name', 'description')
inlines = [ImageInline]
list_filter = ('type',)
search_fields = ('name', 'description')
Note this doesn't happen all the time, it only happens when trying to edit a
_specific_ project (and I'm assuming it might happen with others as well, but
so far couldn't find more examples).
Any ideas? Thanks in advanced!
Answer: Got same error, update Pillow, it helps.
$ pip install pillow --upgrade
|
to clustter the floating point data into suitable buckets in python
Question: I have a csv file which has thousands of floating point values arranged in
ascending order. I want to bunch/cluster those values into suitable clusters.
for example :
0.001
0.002
0.013
0.1
0.101
0.12
0.123
0.112
0.113
0.2
so the clusters should be like
0 - 0.1 with count 4
0.1 - 0.2 with count 6
How can I do this clustering task automatically in python ? Do I need to keep
some initial parameters? I have no clue in this regard. Please help.
Answer: You can `bisect.bisect_left` to find where the element would land in a list of
keys with the correct increment, then simply use that index to get the element
from the list of keys and increment its count using a dict.
from bisect import bisect_left
with open("test.txt") as f:
keys = [0.1, 0.2]
d = dict.fromkeys(keys, 0)
for line in f:
ind = bisect_left(keys, float(line))
d[keys[ind]] += 1
print(d)
{0.1: 4, 0.2: 6}
Another way would be to round by an appropriate amount:
with open("test.txt") as f:
keys = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6]
d = dict.fromkeys(keys, 0)
for flt in map(float, f):
k = round(flt + .05, 1) if flt > .05 else .1
if flt not in d:
d[k] += 1
else:
d[flt] += 1
|
Can monads do what this OOP can't?
Question: Trying to understand monads and wondering if they'd be useful for data
transformation programming in Python, I looked at many introductory
explanations. But I don't understand why monads are important.
Is the following Python code a good representation of the Maybe monad?
class Some:
def __init__(self, val):
self.val=val
def apply(self, func):
return func(self.val)
class Error:
def apply(self, func):
return Error()
a = Some(1)
b = a.apply(lambda x:Some(x+5))
Can you give an example of a monad solution, which cannot be transformed into
such OOP code?
(Do you think monads for data transformation in OOP languages can be useful?)
Answer: Here is a post that discusses monads using Swift as the language that might
help you make more sense of them: <http://www.javiersoto.me/post/106875422394>
The basic point is that a monad is an object that has three components.
1. A constructor that can take some other object, or objects, and create a monad wrapping that object.
2. A method that can apply a function _that knows nothing about the monad_ to its contents and return the result wrapped in a monad.
3. A method that can apply a function that takes the raw object and returns a result wrapped in the monad, and return that monad.
Note that this means even an Array class can be a monad if the language treats
methods as first class objects, and the necessary methods exist.
If the language doesn't treat methods as first class objects, _even if it's an
OO language_ , it will not able able to implement Monads. I think your
confusion may be coming from the fact that you are using a multi-paradigm
language (Python) and assuming it is a pure OO language.
|
how to pass python json object to django template
Question: I want to pass some data(dict format) from views to template. And then in the
template I want to transform it to json format, so that it can be used in
javascript. But I tried to use json filter, it turns out it is not a valid
filter in django. I also tried to use pass a json data in the context
dictionary like this, but I get an error in the template, it says the data is
not JSON serializable. i know there is a way to make a another ajax call just
to get json data. But I want to get the data in the initial call.
items = models.Model1.objects.all()
itmes = json.dumps(items)
return render(request, "index.html", {"items":items})
The template I try to use is
<script type="text/javascript">
var data = {{ items}};
$('#table').DataTable( {
data: data,});
</script>
# model
class Model1(models.Model):
token = models.CharField(max_length=100)
flag = models.BooleanField(default = False)
Answer: You don't have to pass it to template and then transform it to json. You can
directly return a string response.
import json
return HttpResponse(json.dumps({"item":items}))
|
Python version check
Question: When I did like this for checking python version installed
python -version
the result was like this-
Python 2.7.6
when I checked like this-
python -v
result was like this-
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# /usr/lib/python2.7/site.pyc matches /usr/lib/python2.7/site.py
import site # precompiled from /usr/lib/python2.7/site.pyc
# /usr/lib/python2.7/os.pyc matches /usr/lib/python2.7/os.py
import os # precompiled from /usr/lib/python2.7/os.pyc
import errno # builtin
import posix # builtin
# /usr/lib/python2.7/posixpath.pyc matches /usr/lib/python2.7/posixpath.py
import posixpath # precompiled from /usr/lib/python2.7/posixpath.pyc
# /usr/lib/python2.7/stat.pyc matches /usr/lib/python2.7/stat.py
import stat # precompiled from /usr/lib/python2.7/stat.pyc
# /usr/lib/python2.7/genericpath.pyc matches /usr/lib/python2.7/genericpath.py
import genericpath # precompiled from /usr/lib/python2.7/genericpath.pyc
# /usr/lib/python2.7/warnings.pyc matches /usr/lib/python2.7/warnings.py
import warnings # precompiled from /usr/lib/python2.7/warnings.pyc
# /usr/lib/python2.7/linecache.pyc matches /usr/lib/python2.7/linecache.py
import linecache # precompiled from /usr/lib/python2.7/linecache.pyc
# /usr/lib/python2.7/types.pyc matches /usr/lib/python2.7/types.py
import types # precompiled from /usr/lib/python2.7/types.pyc
# /usr/lib/python2.7/UserDict.pyc matches /usr/lib/python2.7/UserDict.py
import UserDict # precompiled from /usr/lib/python2.7/UserDict.pyc
# /usr/lib/python2.7/_abcoll.pyc matches /usr/lib/python2.7/_abcoll.py
import _abcoll # precompiled from /usr/lib/python2.7/_abcoll.pyc
# /usr/lib/python2.7/abc.pyc matches /usr/lib/python2.7/abc.py
import abc # precompiled from /usr/lib/python2.7/abc.pyc
# /usr/lib/python2.7/_weakrefset.pyc matches /usr/lib/python2.7/_weakrefset.py
import _weakrefset # precompiled from /usr/lib/python2.7/_weakrefset.pyc
import _weakref # builtin
# /usr/lib/python2.7/copy_reg.pyc matches /usr/lib/python2.7/copy_reg.py
import copy_reg # precompiled from /usr/lib/python2.7/copy_reg.pyc
# /usr/lib/python2.7/traceback.pyc matches /usr/lib/python2.7/traceback.py
import traceback # precompiled from /usr/lib/python2.7/traceback.pyc
# /usr/lib/python2.7/sysconfig.pyc matches /usr/lib/python2.7/sysconfig.py
import sysconfig # precompiled from /usr/lib/python2.7/sysconfig.pyc
# /usr/lib/python2.7/re.pyc matches /usr/lib/python2.7/re.py
import re # precompiled from /usr/lib/python2.7/re.pyc
# /usr/lib/python2.7/sre_compile.pyc matches /usr/lib/python2.7/sre_compile.py
import sre_compile # precompiled from /usr/lib/python2.7/sre_compile.pyc
import _sre # builtin
# /usr/lib/python2.7/sre_parse.pyc matches /usr/lib/python2.7/sre_parse.py
import sre_parse # precompiled from /usr/lib/python2.7/sre_parse.pyc
# /usr/lib/python2.7/sre_constants.pyc matches /usr/lib/python2.7/sre_constants.py
import sre_constants # precompiled from /usr/lib/python2.7/sre_constants.pyc
# /usr/lib/python2.7/_sysconfigdata.pyc matches /usr/lib/python2.7/_sysconfigdata.py
import _sysconfigdata # precompiled from /usr/lib/python2.7/_sysconfigdata.pyc
# /usr/lib/python2.7/plat-x86_64-linux-gnu/_sysconfigdata_nd.pyc matches /usr/lib/python2.7/plat-x86_64-linux-gnu/_sysconfigdata_nd.py
import _sysconfigdata_nd # precompiled from /usr/lib/python2.7/plat-x86_64-linux-gnu/_sysconfigdata_nd.pyc
# /usr/lib/python2.7/sitecustomize.pyc matches /usr/lib/python2.7/sitecustomize.py
import sitecustomize # precompiled from /usr/lib/python2.7/sitecustomize.pyc
import encodings # directory /usr/lib/python2.7/encodings
# /usr/lib/python2.7/encodings/__init__.pyc matches /usr/lib/python2.7/encodings/__init__.py
import encodings # precompiled from /usr/lib/python2.7/encodings/__init__.pyc
# /usr/lib/python2.7/codecs.pyc matches /usr/lib/python2.7/codecs.py
import codecs # precompiled from /usr/lib/python2.7/codecs.pyc
import _codecs # builtin
# /usr/lib/python2.7/encodings/aliases.pyc matches /usr/lib/python2.7/encodings/aliases.py
import encodings.aliases # precompiled from /usr/lib/python2.7/encodings/aliases.pyc
# /usr/lib/python2.7/encodings/utf_8.pyc matches /usr/lib/python2.7/encodings/utf_8.py
import encodings.utf_8 # precompiled from /usr/lib/python2.7/encodings/utf_8.pyc
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
dlopen("/usr/lib/python2.7/lib-dynload/readline.x86_64-linux-gnu.so", 2);
import readline # dynamically loaded from /usr/lib/python2.7/lib-dynload/readline.x86_64-linux-gnu.so
>>>
It looks like I have multiple versions of python installed which are causing
problems while installing modules using pip. Even after installing django
manage.py runserver shows error regarding unable to find django.core something
something. How to solve this problem? Please help!!
Answer: python -v is for 'verbose':
-v : verbose (trace import statements); also PYTHONVERBOSE=x
can be supplied multiple times to increase verbosity
Note it is **lowercase**
`python -V` will give you the version. (uppercase v)
|
Find included range from a range given excluded range in python
Question: I have a range say (0,1000). My another input will be excluded range
[(200,400), (600,800)]. I need as output included range [(0,199), (401,599),
(801,1000)].
How do I implement this in python?
Answer: You can [chain
iterables](https://docs.python.org/2/library/itertools.html#itertools.chain)
together:
from itertools import chain
for i in chain(range(1,200), range(401, 600), range(801, 1001)):
# etc
Also, if you've been given the range and can only iterate over it once, you
can use
[**`tee`**](https://docs.python.org/2/library/itertools.html#itertools.tee)
and
[**`islice`**](https://docs.python.org/2/library/itertools.html#itertools.islice):
def excluded(sequence):
first, second, third = tee(sequence, 3)
yield from chain(islice(first, 1, 200),
islice(second, 401, 600),
islice(third, 801, 1001))
for i in excluded(range(0, 1000)):
# etc.
|
Proper use of sep in print
Question: I am new at python, and I am having problems with the use of sep=. What I want
to do is to not have a space between the number `25` and the `.`
Here is my code and the error I get. I am running this code on MAC OSX El
Capitan's Terminal.
code:
side = 5
area = side * side
print "The area of a square with side ",side,"is ",area,".",sep=" "
Output:
print "The area of a square with side ",side,"is ",area,".",sep=" "
^
SyntaxError: invalid syntax
Answer: `sep` is an argument to the [`print()`
_function_](https://docs.python.org/3/library/functions.html#print), which
requires you use Python 3 or use a special `from __future__ import
print_function` statement in Python 2 (see the [`print()` function
documentation](https://docs.python.org/2/library/functions.html#print).
The normal plain vanilla [Python 2 `print`
_statement_](https://docs.python.org/2/reference/simple_stmts.html#the-print-
statement) (which is what you appear to be using) does not support altering
the separator used.
Since the separator is _always_ a space, you don't need to specify it here at
all:
print "The area of a square with side ", side, "is ", area, "."
If you wanted to print _without_ spaces, use string formatting instead:
print "The area of a square with side {} is {}.".format(side, area)
If you are using a Python 3 tutorial using `print(foo, bar, baz sep='')` or
similar similar syntax, get yourself Python 3 installed, or get yourself a
Python 2 specific tutorial instead.
|
Numbers in a Matrix
Question: I tried to solve the following problem with Python:
[](http://i.stack.imgur.com/TK8zK.png)
But I got stuck at generating a single valid table. I was expecting the
program to display a valid matrix, but in order for the program to continue
and not print `None`, I had to assign a `7` for a square that has no
possibles. What should be fixed?
My code so far:
from pprint import pprint
import sys
import random
sys.setrecursionlimit(10000)
def getPossiblesForSquare(sqx,sqy,matrix):
'''Gets the possible entries of matrix[sqy][sqx].
Assumes it equals 0.'''
assert matrix[sqy][sqx]==0
# get the row that it is on
rowon=matrix[sqy]
# columns are a little trickier
colon=[matrix[row][sqx] for row in range(5)]
# find the possibilities!
possibles=list(range(1,7))
for item in list(set(rowon+colon)): # remove duplicates
if not (item == 0) and (item in possibles):
del possibles[possibles.index(item)]
random.shuffle(possibles)
return possibles
def getPossiblesForMatrix(matrix):
'''Gets all the possible squares for a matrix.'''
possiblesdict={}
for y in range(6):
for x in range(6):
if matrix[y][x]==0:
possiblesdict[(y,x)]=getPossiblesForSquare(x,y,MATRIX)
return possiblesdict
def flattenList(matrix):
result=[]
for i in matrix:
if not isinstance(i,list):
result+=[i]
else:
result+=flattenList(i)
return result
def getPossibleMatrix(startMatrix, iteration=0, yon=1, prevZeroInd=None):
if 0 not in flattenList(startMatrix):
print('RESULT:\n\n')
return startMatrix
else:
# find&fill in the first blank one
ind=flattenList(startMatrix).index(0)
y=ind//6
x=ind%6
if (x,y)==prevZeroInd:
startMatrix[y][x]=7
else:
possibles=getPossiblesForSquare(x,y,startMatrix)
if len(possibles)==0:
startMatrix[y][x]=7
else:
startMatrix[y][x]=possibles[0]
if iteration <= 6:
return getPossibleMatrix(startMatrix, iteration+1, yon, (x,y)) # <<BUG
else:
if yon!=4:
return getPossibleMatrix(startMatrix, 0, yon+1, (x,y))
MATRIX=[[1,2,3,4,5,6],
[2,0,0,0,0,5],
[3,0,0,0,0,4],
[4,0,0,0,0,3],
[5,0,0,0,0,2],
[6,5,4,3,2,1]]
result=getPossibleMatrix(MATRIX)
pprint(result)
Answer: ## Why your script hangs:
* * *
Essentially your script encounters problems here:
for item in list(set(rowon + colon)): # remove duplicates
if not (item == 0) and (item in possibles):
del possibles[possibles.index(item)]
* At the third iteration, for the third cell your if condition is evaluated as true for all possible values `[1 to 6]` (if you output the matrix you will see that the `set()` you are creating contains all elements), so you always return zero, re-check the values, return zero [**_ad infinitum_**](https://en.wikipedia.org/wiki/Ad_infinitum).
If you're looking to brute-force a solution out of this, you might want to
update the `sqx` and `sqy` to go to a different cell when possibles is empty.
Another additional small mistake I located was:
# you are checking values 1-5 and not 1-6!
possibles = list(range(1, 6)) # should be range(7) [exclusive range]
* Don't forget that range is exclusive, it doesn't include (excludes) the upper limit.
There exist of course, different ways to tackle this problem.
* * *
## A possible -alternate- solution:
> Read this for the general, alternate view of how to solve this. If you do
> not want to see a possible solution, skip the 'code' part.
* * *
The solution matrix (one of the possible ones) has this form (unless I am
making a horrible mistake):
MATRIX = [[1, 2, 3, 4, 5, 6],
[2, 3, 6, 1, 4, 5],
[3, 1, 5, 2, 6, 4],
[4, 6, 2, 5, 1, 3],
[5, 4, 1, 6, 3, 2],
[6, 5, 4, 3, 2, 1]]
The Logic is as follows:
You must observe the symmetry present in the matrix. Specifically, every row
and every column displays a 'flip and reverse' symmetry. For example, the
first and last rows are connected by this equation :
row[0] = REV(flip(row[n]))
Similarly, all additional rows (or columns) have their corresponding
counterpart:
row[1] = REV(flip(row[n-1]))
and so on.
So, for `n=6` this essentially boils down to finding the `(n / 2) -1` (because
we already know the first and last row!) and afterwards flipping them (not the
finger), reversing them and assigning them to their corresponding rows.
In order to find these values we can observe the matrix as a combination of
smaller matrices:
These make the first two (unknown) rows of the matrix:
sub_matrix = [[1, 2, 3, 4, 5, 6],
[2, 0, 0, 0, 0, 5],
[3, 0, 0, 0, 0, 4],
[6, 5, 4, 3, 2, 1]]
and the other two rows can be made by finding the correct values for these
two.
Observe the restrictions in hand:
In column `[1][1]` and `[1][m-1]` we cannot:
* place a `2` or a `5`
In columns `[1][2]` and `[1][m-2]` we cannot:
* place the previous values (`[2, 5]`) along with (`[3, 4]`) so, we cannot have a value `in` `[2,3,4,5]`
For the inner columns we're left with the set `set(1-6) - set(2-5) = [1, 6]`
and since we get a normal row and a **_single_** inverted and flipped row for
this, we can arbitrarily select a value and add it as a column value.
By using another list we can keep track of the values used and fill out the
rest of the cells.
* * *
### Coding this: (Spoilers)
* * *
**Note** : I did not use `numpy` for this. You **can** and **should** though.
(Also, `Python 2.7`)
Also, I did not use recursion for this (you can try to, by finding the same
matrix for bigger values of `n` [I believe it's a good fit for a recursive
function].
First, in order to not type this all the time, you can create a `n x n` matrix
as follows: (This isn't much of a spoiler.)
# our matrix must be n x n with n even.
n = 6
# Create n x n matrix.
head = [i for i in xrange(1, n + 1)] # contains values from 1 to n.
zeros = [0 for i in xrange(1, n-1)] # zeros
tail = [i for i in xrange(n, 0, -1)] # contains values from n to 1.
# Add head and zeros until tail.
MATRIX = [([j] + zeros + [(n+1)-j]) if j != 1 else head for j in xrange(1, n)]
# Add tail
MATRIX.append(tail)
Then, create the smaller `(n/2 + 1) x n` array:
# Split matrix and add last row.
sub_matrix = MATRIX[:(n / 2)] + [tail]
Afterwards, a small function called `sub = fill_rows(sub_matrix)` comes in and
takes care of business:
def fill_rows(mtrx):
# length of the sub array (= 4)
sub_n = len(mtrx)
# From 1 because 0 = head
# Until sub_n -1 because the sub_n - 1 is = tail (remember, range is exclusive)
for current_row in xrange(1, sub_n - 1):
print "Current row: " + str(current_row)
# -- it gets messy here --
# get values of inner columns and filter out the zeros (matrix[row][n / 2] == 0 evaluates to False)
col_vals_1 = [mtrx[row][n / 2] for row in xrange(0, sub_n) if mtrx[row][(n / 2)]]
col_vals_2 = [mtrx[row][(n / 2) - 1] for row in xrange(0, sub_n) if mtrx[row][(n / 2) - 1]]
col_vals = col_vals_1 + col_vals_2
# print "Column Values = " + str(col_vals)
row_vals = [mtrx[current_row][col] for col in xrange(0, n) if mtrx[current_row][col]]
# print "Row Values = " + str(row_vals)
# Find the possible values by getting the difference of the joined set of column + row values
# with the range from (1 - 6).
possible_values = list(set(xrange(1, n + 1)) - set(row_vals + col_vals))
print "Possible acceptable values: " + str(possible_values)
# Add values to matrix (pop to remove them)
# After removing add to the list of row_values in order to check for the other columns.
mtrx[current_row][(n-1)/2] = possible_values.pop()
row_vals.append(mtrx[current_row][(n - 1) / 2])
mtrx[current_row][(n-1)/2 + 1] = possible_values.pop()
row_vals.append(mtrx[current_row][(n-1) / 2 + 1])
# New possible values for remaining columns of the current row.
possible_values = list(set(xrange(1, n + 1)) - set(row_vals))
print "Possible acceptable values: " + str(possible_values)
# Add values to the cells.
mtrx[current_row][(n - 2)] = possible_values.pop()
mtrx[current_row][1] = possible_values.pop()
# return updated sub-matrix.
return mtrx
The only thing left to do now is take those two rows, flip them, reverse them
and add the head and tail to them:
print '=' * 30 + " Out " + "=" * 30
# Remove first and last rows.
del sub[0]
sub.pop()
# reverse values in lists
temp_sub = [l[::-1] for l in sub]
# reverse lists in matrix.
temp_sub.reverse()
# Add them and Print.
pprint([head] + sub + temp_sub + [tail])
This outputs what, I hope, is the right matrix:
============================== Out ==============================
[[1, 2, 3, 4, 5, 6],
[2, 3, 6, 1, 4, 5],
[3, 1, 5, 2, 6, 4],
[4, 6, 2, 5, 1, 3],
[5, 4, 1, 6, 3, 2],
[6, 5, 4, 3, 2, 1]]
* * *
### Additionally
* * *
By using this way of solving it the answer to the problem in hand becomes more
easy. Viewing the matrix as a combination of these sub-matrices you can tell
how many of these combinations might be possible.
As a closing note, it would be a good work-out to modify it a bit in order to
allow it to find this array for an arbitrary (**_but even_**) number of `n`.
|
Add an image in a specific position in the document (.docx) with Python?
Question: I use Python-docx to generate Microsoft Word document.The user want that when
he write for eg: "Good Morning every body,This is my %(profile_img)s do you
like it?" in a HTML field, i create a word document and i recuper the picture
of the user from the database and i replace the key word %(profile_img)s by
the picture of the user **NOT at the END OF THE DOCUMENT**. With Python-docx
we use this instruction to add a picture:
document.add_picture('profile_img.png', width=Inches(1.25))
The picture is added to the document but the problem that it is added at the
end of the document. Is it impossible to add a picture in a specific position
in a microsoft word document with python? I've not found any answers to this
in the net but have seen people asking the same elsewhere with no solution.
Thanks (note: I'm not a hugely experiance programmer and other than this
awkward part the rest of my code will very basic)
Answer: Quoting [the python-docx documentation](https://python-
docx.readthedocs.org/en/latest/user/shapes.html):
> The Document.add_picture() method adds a specified picture to the end of the
> document in a paragraph of its own. However, by digging a little deeper into
> the API you can place text on either side of the picture in its paragraph,
> or both.
When we "dig a little deeper", we discover the
[`Run.add_picture()`](https://python-
docx.readthedocs.org/en/latest/api/text.html#docx.text.run.Run.add_picture)
API.
Here is an example of its use:
from docx import Document
from docx.shared import Inches
document = Document()
p = document.add_paragraph()
r = p.add_run()
r.add_text('Good Morning every body,This is my ')
r.add_picture('/tmp/foo.jpg')
r.add_text(' do you like it?')
document.save('demo.docx')
|
Error while installing PyGraphviz (Mac OS X, Anaconda)
Question: I'm having trouble while installing PyGraphviz. I'm using Anaconda in Mac OS
X.
Error messages indicates some reasons, but I already checked out it is
installed in anaconda directory.
Sundongui-MacBook-Pro:site-packages sundong$ pwd
/Users/sundong/anaconda/lib/python2.7/site-packages
Sundongui-MacBook-Pro:site-packages sundong$ pip install graphviz --upgrade
Requirement already up-to-date: graphviz in /Users/sundong/anaconda/lib/python2.7/site-packages
According to the error messages, How can I change the the include_dirs and
library_dirs variables in setup.py??
Here is the error message that I meet
Sundongui-MacBook-Pro:anaconda sundong$ pip install pygraphviz
Collecting pygraphviz
Using cached pygraphviz-1.3.1.tar.gz
Building wheels for collected packages: pygraphviz
Running setup.py bdist_wheel for pygraphviz
Complete output from command /Users/sundong/anaconda/bin/python -c "import setuptools;__file__='/private/var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/pip-build-bLb4AR/pygraphviz/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d /var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/tmpwR_08Dpip-wheel-:
running bdist_wheel
running build
running build_py
creating build
creating build/lib.macosx-10.5-x86_64-2.7
creating build/lib.macosx-10.5-x86_64-2.7/pygraphviz
copying pygraphviz/__init__.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
copying pygraphviz/agraph.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
copying pygraphviz/graphviz.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
copying pygraphviz/release.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
copying pygraphviz/version.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
creating build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/__init__.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_attribute_defaults.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_attributes.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_clear.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_drawing.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_edge_attributes.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_graph.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_html.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_layout.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_node_attributes.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_readwrite.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_string.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_subgraph.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
copying pygraphviz/tests/test_unicode.py -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz/tests
running egg_info
writing pygraphviz.egg-info/PKG-INFO
writing top-level names to pygraphviz.egg-info/top_level.txt
writing dependency_links to pygraphviz.egg-info/dependency_links.txt
warning: manifest_maker: standard file '-c' not found
reading manifest file 'pygraphviz.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
warning: no previously-included files matching '*~' found anywhere in distribution
warning: no previously-included files matching '*.pyc' found anywhere in distribution
warning: no previously-included files matching '.svn' found anywhere in distribution
no previously-included directories found matching 'doc/build'
writing manifest file 'pygraphviz.egg-info/SOURCES.txt'
copying pygraphviz/graphviz.i -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
copying pygraphviz/graphviz_wrap.c -> build/lib.macosx-10.5-x86_64-2.7/pygraphviz
running build_ext
building 'pygraphviz._graphviz' extension
creating build/temp.macosx-10.5-x86_64-2.7
creating build/temp.macosx-10.5-x86_64-2.7/pygraphviz
gcc -fno-strict-aliasing -I/Users/sundong/anaconda/include -arch x86_64 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/Users/sundong/anaconda/include/python2.7 -c pygraphviz/graphviz_wrap.c -o build/temp.macosx-10.5-x86_64-2.7/pygraphviz/graphviz_wrap.o
pygraphviz/graphviz_wrap.c:2954:10: fatal error: 'graphviz/cgraph.h' file not found
#include "graphviz/cgraph.h"
^
1 error generated.
error: command 'gcc' failed with exit status 1
----------------------------------------
Failed building wheel for pygraphviz
Failed to build pygraphviz
Installing collected packages: pygraphviz
Running setup.py install for pygraphviz
Complete output from command /Users/sundong/anaconda/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/pip-build-bLb4AR/pygraphviz/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/pip-qgosXm-record/install-record.txt --single-version-externally-managed --compile:
running install
Trying pkg-config
Failed to find pkg-config
Trying dotneato-config
Failed to find dotneato-config
Failed to find dotneato-config
Your Graphviz installation could not be found.
1) You don't have Graphviz installed:
Install Graphviz (http://graphviz.org)
2) Your Graphviz package might incomplete.
Install the binary development subpackage (e.g. libgraphviz-dev or similar.)
3) You are using Windows
There are no PyGraphviz binary packages for Windows but you might be
able to build it from this source. See
http://networkx.lanl.gov/pygraphviz/reference/faq.html
If you think your installation is correct you will need to manually
change the include_dirs and library_dirs variables in setup.py to
point to the correct locations of your graphviz installation.
The current setting of library_dirs and include_dirs is:
library_dirs=None
include_dirs=None
error: Error locating graphviz.
----------------------------------------
Command "/Users/sundong/anaconda/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/pip-build-bLb4AR/pygraphviz/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/pip-qgosXm-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/var/folders/p6/rjy4tf353bzfy7gsl5jn_yvc0000gn/T/pip-build-bLb4AR/pygraphviz
Answer: try the following (make sure to have anaconda-client installed and updated):
conda install --channel https://conda.anaconda.org/garylschultz pygraphviz
|
Python time.sleep() does not work in linux and multi thread
Question: I write a simple multiprocess and multi-thread code in python which works in
windows but doesn't work in linux (i tested it on freebsd and ubuntu)
import threading
import time
from multiprocessing import Process
class Test(threading.Thread):
def run(self):
print('before sleep')
time.sleep(1)
print('after sleep')
def run_test():
Test().start()
if __name__ == "__main__":
Process(target=run_test, args=()).start()
this program only print "before sleep" and then exit.
why sleep doesn't work here? (it works on windows)
UPDATE:
I used join() in my process like this, but still not work.
...
if __name__ == "__main__":
pr = Process(target=run_test, args=())
pr.start()
pr.join()
Answer: The join() should be used in the calling thread to wait for another thread:
def run_test():
t = Test()
t.start()
t.join()
|
Django custom auth backend doesn't seem to be being called?
Question: I'm using Django 1.8.4 on Python 3, and attempting to create an auth backend
which validates a cookie from a legacy ColdFusion web site and create / log
the Django user in after checking the value in a database. In settings, I am
including the backend:
AUTHENTICATION_BACKENDS = (
'site_classroom.cf_auth_backend.ColdFusionBackend',
)
And the code for the backend itself; SiteCFUser is a model against the SQL
Server database user model which contains the active cookie token value:
from django.contrib.auth.backends import ModelBackend
from django.contrib.auth import get_user_model
from users.models import SiteCFUser
class ColdFusionBackend(ModelBackend):
"""
Authenticates and logs in a Django user if they have a valid ColdFusion created cookie.
ColdFusion sets a cookie called "site_web_auth"
Example cookie: authenticated@site+username+domain+8E375588B1AAA9A13BE03E401A02BC46
We verify this cookie in the MS SQL database 'site', table site_users, column user_last_cookie_token
"""
def authenticate(self, request):
User = get_user_model()
print('Hello!')
token=request.COOKIES.get('site_web_auth', None)
print('Token: ' + token)
cookie_bites = token.split('+')
if cookie_bites[0] != "authenticated@site":
# Reality check: not a valid site auth cookie
return None
username = cookie_bites[1]
cf_token = cookie_bites[3]
try:
site_user = SiteCFUser.objects.using('mssqlsite').filter(cf_username=username)
except:
# No user found; redirect to login page
return None
if site_user[0].cftoken == cf_token:
try:
# Does the user exist in Django?
user = User.objects.get(username=username)
except:
# User does not exist, has a valid cookie, create the User.
user = User(username=username)
user.first_name = site_user[0].cf_first_name
user.last_name = site_user[0].cf_last_name
user.email = site_user[0].cf_email
user.save()
else:
return None
def get_user(self, user_id):
User = get_user_model()
try:
return User.objects.get(pk=user_id)
except User.DoesNotExist:
return None
The problem is, the backend doesn't seem to be called when hitting a URL with
a view with `@login_required`, or even trying to log in through a form with
username and password. If I force an error by changing the name of the class
in settings, or change the name of the class in cf_auth_backend.py, I do get
an error. However, none of the print statements show up in the console. I'm
clearly missing something here: any idea what I'm not doing right?
Answer: Authentication backends doesn't work that way. They won't be called on each
request or on requests where authentication is required.
If you want to log in user based on some cookie, you should call
authentication in middleware.
|
Issue to play a mp3 file with a Python script from Arduino data
Question: I am trying to perform the following action with an Arduino Uno and a Python
script: if the length calculated by the ultrawave sensor of Arduino is below
36 then play a music which is on my hard drive.
My Python code is the following one:
import serial, webbrowser
arduino = serial.Serial('/dev/ttyACM0', 9600)
data = arduino.readline()
while (1==1):
if (arduino.inWaiting()>0) and data < 36:
webbrowser.open("/home/path/my-music.mp3")
But nothing is happening when I am launching it, the script kept running in my
shell. If I perform a print data I noticed that the value of data is different
from the Arduino console and it seems that the Arduino console is not working
properly (the length value of the ultrawave sensor seem truncated) when the
Python script is running at the same time.
when I run the following Python script:
import serial, webbrowser
webbrowser.open("/home/path/my-music.mp3")
My mp3 is played properly. Any ideas?
Answer: I modified your script to tell you what is happening. I can not test it out.
# import the modules
import serial
import webbrowser
# open a serial connection to the Arduino to read data from
arduino = serial.Serial('/dev/ttyACM0', 9600)
# we want to read everything the Arduino tells us
while True:
# read one line (a str) that the Arduino wrote with Serial.println()
line = arduino.readline()
# convert the line into a string that contains only the numbers
# by stripping away the line break characters and spaces
string_with_number_in_it = line.strip()
# convert the string into a number that can be compared
number = float(string_with_number_in_it)
if number < 36:
webbrowser.open("/home/path/my-music.mp3")
Also, I suggest you install [mplayer](https://en.wikipedia.org/wiki/MPlayer)
and use it instead of the webbrowser.
import subprocess
def play_music_file(filename):
subprocess.call(('mplayer', filename))
|
parse a file for a line with specific text, then logic to determine next steps
Question: I am trying to scan a textfile for a specific keyword. When this keyword is
found there's a numeric value on the line that I need to compare to see if
it's less than a set value. If it is, the following lines in the file need to
be printed/saved until the next keyword is reached. I hope this makes sense.
Example of the textfile:
"saleAmount","500",
text text text
etc etc etc
text text text
"saleAmount","1200",
text text text
etc etc etc
text text text
My python file is as follows:
import re
info = open("results.txt", "r")
for line in info:
if re.match("(.*)saleAmount(.*)", line):
for s in line:
result=re.findall('\d+', s)
if (result < 1000)
print (result)
In this case the line with the amount of 500 should be compared to 1000 and
printed, as should the following 2 lines. The line with the amount of 1200 and
it's following lines will be ignored.
I can get this to print out the values in a weird one digit a line result but
when I add in the comparison I can't get that.
I'm sure this is simple but I'm new to python. Thanks
Answer: Here's one possible solution:
import re
ls=[]
with open('results.txt') as f:
for line in f:
if "saleAmount" in line:
ls.append(line.strip('\n'))
for num in range(len(ls)):
for amnt in re.findall('\d+',ls[num]):
if int(amnt) < 1000:
print(amnt)
What I did is added the file that contain `saleAmount` to a list `ls`, then
extracted the numbers and from that list and compared to see if they are less
than 1000.
In your case, `result` is obtaining the values whether it contains a number
(splits up that number into single digit) or if it contains a string (becomes
empty list).
In your original code, try `print(result)` right after you define it without
the `if` statement and what's below it. Then you'll get a clearer
understanding as to why you can't compare it to 1000
Edit: Include "saleAmount" and following lines
import re
ls=[]
with open('data.csv') as f:
for line in f:
ls.append(line)
for w in ls:
if "saleAmount" in w and int(re.findall('\d+',w)[0]) < 1000:
print(w)
for i in range(1,4):
print(ls[ls.index(w)+i])
|
Incrementally and statistically measuring samples with Python (Numpy, Pandas, etc) and performance
Question: Let's say I take a stream of incoming data (very fast) and I want to view
various stats for a window (std deviation, (say, the last N samples, N being
quite large). What's the most efficient way to do this with Python?
For example,
df=ps.DataFrame(np.random.random_sample(200000000))
df2 = df.append([5])
Is crashing my REPL environment in visual studio.
Is there a way to append to an array without this happening? Is there a way to
tell which operations on the dataframe are computed incrementally other than
by doing timeit on them?
Answer: I recommend building a circular buffer out of a numpy array.
This will involve keeping track of an index to your last updated point, and
incrementing that when you add a new value.
import numpy as np
circular_buffer = np.zeros(200000000, dtype=np.float64)
head = 0
# stream input
circular_buffer[head] = new_value
if head == len(circular_buffer) - 1:
head = 0
else:
head += 1
Then you can compute the statistics normally on circular_buffer.
### If You Don't Have Enough RAM
Try implementing something similar in
[bquery](https://github.com/visualfabriq/bquery) and
[bcolz](https://github.com/Blosc/bcolz). These store your data more
efficiently than numpy (using compression) and offer similar performance.
Bquery now has mean and standard deviation. _Note: I'm a contributer to
bquery_
|
How to fake javascript enabled in Python requests/beautifulsoup
Question: I'm trying to crawl a website which return an error message that your js is
disabled and you might be a bot. I tried to see same behaviour in web browser
and yes the same response, however if JavaScript is enabled it will not affect
the original response, I mean original response is not dependent on JS.
So I was thinking if I can tell the web/http server that my JS is enabled and
I'm not a BOT. is this possible in Python requests library, or any other
python library for that matter?
And yeah I've set the `User-Agent` header, even all other headers, like
`host`, `language`, `connection`, etc
Answer: If the site is just checking whether javascript can be executed or not through
executing some js, use selenium to get the page, and then use BeautifulSoup to
parse the page that selenium got.
from bs4 import BeautifulSoup
from selenium import webdriver
driver = webdriver.Firefox()
driver.get('http://your-site/url')
html = driver.page_source
soup = BeautifulSoup(html)
...
|
Python Dictionary of States
Question: I am writing a program that uses a dictionary of 50 states. This program. will
ask users about 8 questions and after the user answer the questions, it will
out some thing like 'based on your answer, you should live in this state'. it
is a randomized output of state. The questions will loop around until the user
decided to stop. This is what I have thus far. Can you help? Thank you
import random
def main():
states = {
'Alabama','Alaska','Arizona','Arkansas','California','Colorado',
'Connecticut','Delaware','Florida','Georgia','Hawaii','Idaho',
'Illinois','Indiana','Iowa','Kansas','Kentucky','Louisiana',
'Maine' 'Maryland','Massachusetts','Michigan','Minnesota',
'Mississippi', 'Missouri','Montana','Nebraska','Nevada',
'New Hampshire','New Jersey','New Mexico','New York',
'North Carolina','North Dakota','Ohio',
'Oklahoma','Oregon','Pennsylvania','Rhode Island',
'South Carolina','South Dakota','Tennessee','Texas','Utah',
'Vermont','Virginia','Washington','West Virginia',
'Wisconsin','Wyoming'
}
print('What city are you from')
city = input()
print('What is your favorite team?')
team = input()
print('What state is close to you?')
state = input()
print('What is the name of your Governor?')
governor = input()
print('What is the name of your Senator?')
senator = input()
print('what is the name of your Sherif?')
sherif = input()
print('What is your favorite baseball team?')
baseball = input()
print('What is your favorite basketball team?')
basketball = input()
print('What is your favorite hockey team?')
hockey = input()
print ('Base on your answer the state you should live in is:' + states)
Answer: First the states you provide is not a dictionary but a set. Try:
type(states)
For having a random choice. First convert if to a list and then choose as
below.
import random
states_list = list(states)
choice = random.choice(states_list)
So in final line include
print ('Base on your answer the state you should live in is: ' + choice)
|
Setup.py woes: WARNING: '' not a valid package name
Question: For my Python project, I keep my source code in the directory `src`. Thus, for
my project's setup.py script:
from setuptools import setup
setup(name='pyIAST',
...
package_dir={'':'src'},
packages=[''])
so that it looks for `src/IAST.py`, where my code resides. e.g. there is a
function `plot_isotherms()` in my `IAST.py` script so the user can, after
installation, call it:
import IAST
IAST.plot_isotherms()
Everything works great, but there is an annoying warning when I `python
setup.py install` or use `pip install pyIAST` from PyPi:
WARNING: '' not a valid package name; please use only.-separated package names in setup.py
How do I make this go away?
My project is [here](https://github.com/CorySimon/pyIAST). I'm also a bit
confused as to why I name my package `pyIAST`, yet the user still types
`import IAST` for my package to import.
Answer: One way to clear that warning is to change your first line to:
`from setuptools import setup, find_packages`
and then change your packages line to:
`packages=find_packages(),`
The setup install will no longer generate a warning.
You can run the following two commands to see your isotherm method is now
available:
`import pyiast` #(<==notice this is not IAST)
`dir(pyiast)`
> `['BETIsotherm', 'InterpolatorIsotherm', 'LangmuirIsotherm',
> 'ModelIsotherm', 'QuadraticIsotherm', 'SipsIsotherm', '_MODELS',
> '_MODEL_PARAMS', '_VERSION', '__author__', '__builtins__', '__doc__',
> '__file__', '__name__', '__package__', 'iast', 'np', 'plot_isotherm',
> 'print_selectivity', 'reverse_iast', 'scipy']`
It can be called using `pyiast.plot_isotherm()`
You may need to update your setuptools. You can check what version you have
with:
`import setuptools; print "setup version: ", setuptools.__version__`
Can update it with: `sudo pip install --upgrade setuptools`
|
Testing in Python whether one glyph is a reflection of another in the same font
Question: Inspired by [List of all unicode's open/close
brackets?](http://stackoverflow.com/questions/13535172/list-of-all-unicodes-
open-close-brackets) I'm trying to find a list of all unicode glyphs in a
given font that are reflections of each other. First I just need to be able to
test whether one glyph is a reflection of another. Below I have two different
attempts (two different implementations of my `render_char` function) but I'm
not able to identify '(' and ')' as mirror images using either one. How can I
do this?
from PIL import Image,ImageDraw,ImageFont
import freetype
import numpy as np
def render_char0(c):
# Based on https://github.com/rougier/freetype-py/blob/master/examples/hello-world.py
# Needs numpy (blech) and the image comes out the inverse of the way I expect
face = freetype.Face("/Library/Fonts/Verdana.ttf")
face.set_char_size( 48*64 )
face.load_char(c)
bitmap = face.glyph.bitmap
w,h = bitmap.width, bitmap.rows
Z = np.array(bitmap.buffer, dtype=np.ubyte).reshape(h,w)
return Image.fromarray(Z, mode='L').convert('1')
def render_char1(c):
# Based on http://stackoverflow.com/a/14446201/2829764
verdana_font = ImageFont.truetype("/Library/Fonts/Verdana.ttf", 20, encoding="unic")
text_width, text_height = verdana_font.getsize(c)
canvas = Image.new('RGB', (text_width+10, text_height+10), (255, 255, 255))
draw = ImageDraw.Draw(canvas)
draw.text((5,5), c, font = verdana_font, fill = "#000000")
return canvas
for render_char in [render_char0, render_char1]:
lparen = render_char('(')
rparen = render_char(')')
mirror = lparen.transpose(Image.FLIP_LEFT_RIGHT)
mirror.show()
rparen.show()
print mirror.tobytes() == rparen.tobytes() # False
Answer: There is a text file called `BidiMirroring.txt` in the Unicode plain-text
database with a list of all mirrored characters. That file is easy to parse by
programs.
Current url is <http://www.unicode.org/Public/UNIDATA/BidiMirroring.txt>
I don't think using the rendered glyphs can work reliably. There's a lot of
reasons why eg. `(` and `)` are no exact mirror images, like spacing around
the character, hinting and anti-aliasing, maybe the font is slightly slanted,
or maybe the font designer has just make the two brackets a bit different etc.
Other characters are rotated, rather than mirrored, like `“` and `”` in some
fonts, and the Chinese quotation marks `「` and `」`.
|
Memory Error when using float32 in dask array
Question: I am trying to import a 1.25 GB dataset into python using **`dask.array`**
The file is a 1312*2500*196 Array of **`uint16`** 's. I need to convert this
to a **`float32`** array for later processing.
I have managed to stitch together this Dask array in `uint16`, however when I
try to convert to `float32` I get a **memory error**.
It doesn't matter what I do to the chunk size, I will always get a memory
error.
I create the array by concatenating the array in lines of 100 (breaking the
2500 dimension up into little pieces of 100 lines, since `dask` can't natively
read `.RAW` imaging files I have to use **`numpy.memmap()`** to read the file
and then create the array. Below I will supply a "as short as possible" code
snippet:
I have tried two methods:
1) Create the full `uint16` array and then try to convert to `float32`:
(note: the `memmap` is a 1312x100x196 array and lines ranges from 0 to 24)
for i in range(lines):
NewArray = da.concatenate([OldArray,Memmap],axis=0)
OldArray = NewArray
return NewArray
and then I use
Float32Array = FinalArray.map_blocks(lambda FinalArray: FinalArray * 1.,dtype=np.float32)
In method 2:
for i in range(lines):
NewArray = da.concatenate([OldArray,np.float32(Memmap)],axis=0)
OldArray = NewArray
return NewArray
Both methods result in a memory error.
**Is there any reason for this?**
I read that `dask` array is capable of doing up to 100 GB dataset
calculations.
I tried all chunk sizes (from as small as 10x10x10 to a single line)
Answer: You can create a dask.array from a numpy memmap array directly with the
`da.from_array` function
x = load_memmap_numpy_array_from_raw_file(filename)
d = da.from_array(x, chunks=...)
You can change the dtype with the `astype` method
d = d.astype(np.float32)
|
Printing contents in particular section of configuration file in Python
Question: Lets imagine i have an config file by name sample.ini, let there be two
section in that.
[section1]
Name1 = Url_1
Name2 = Url_2
[Section2]
Name3 = Url_3
Name4 = Url_4
Now if I want to print Url_3 & Url_4, is there a way in Python that I can only
print those two Url.
I tried looking about this, but they provide solution which print every
section contents in config file.
Please help me with that.
Answer: Could you try giving this a shot? Using python's config parser
sample.ini
[section1]
Name1=Url_1
Name2=Url_2
[Section2]
Name3=Url_3
Name4=Url_4
Script:
import ConfigParser as configparser
parser = configparser.ConfigParser()
parser.read("sample.ini")
section_2 = dict(parser.items("Section2"))
print section_2["name3"]
print section_2["name4"]
Output:
Url_3
Url_4
|
import clr ImportError: No module named clr
Question: I have an Ubuntu 12.04. I tried import clr in my python code and I have this
error.
I went through the links. But all in vain. Is there a way to check 'clr'
present? How do I see that the module is present?
Answer: You need to install Mono framework to run .NET on Ubuntu. Please refer the
below link which helps you to install .NET framework. Then the CLR will be
available for your code OR you can reference the CLR in your code after
installation of Mono.
<http://askubuntu.com/questions/497358/how-to-install-mono-on-
ubuntu-64-bit-v14-04>
|
Python 3 SQLite3 - Incorrect number of bindings
Question: I understand there are MANY questions on Stack Overflow about this error but I
have tried MANY solutions and obviously they have all failed.
Here's a list:
[sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current
statement uses 1, and there are 74
supplied](http://stackoverflow.com/questions/16856647/sqlite3-programmingerror-
incorrect-number-of-bindings-supplied-the-current-sta)
[SQLite parameter substitution
problem](http://stackoverflow.com/questions/228912/sqlite-parameter-
substitution-problem)
[sqlite3.ProgrammingError: Incorrect number of bindings
supplied](http://stackoverflow.com/questions/19473281/sqlite3-programmingerror-
incorrect-number-of-bindings-supplied)
[Reading from database with SQLite and Python: Incorrect number of binding
supplied](http://stackoverflow.com/questions/9986578/reading-from-database-
with-sqlite-and-python-incorrect-number-of-binding-suppli)
[SQLite Python Insert - Incorrect Number of Bindings
Supplied](http://stackoverflow.com/questions/4654513/sqlite-python-insert-
incorrect-number-of-bindings-supplied)
I am trying to store a username and hashed password (created by PassLib -
<https://pythonhosted.org/passlib/> ) in a SQLite3 database. These are stored
in the variables "targetusername" and "password" respectively. My problem is
that when I actually try to insert these 2 variables into a table of a
database called "Passwords", it gives this error:
Incorrect number of bindings supplied. The current statement uses 1, and there are 11 supplied.
Here's an example of what targetusername and password would store:
targetusername = "user4884072"
password = "$5$rounds=535000$ySH31paWMjEDCUUY$jdrBVGsoYnSMkdVBtjCaxQy2f0g3MX1Wts4vSYz7m.4"
This line gives the error:
c.executemany("INSERT INTO {tn} ({idf}, {cn}) VALUES(targetusername, %s" % str(password).\
format(tn="Passwords"))
It has been changed multiple times to try and fix the issue (which apparently
is caused by how Python stores variables), but here is what it was originally:
c.execute("INSERT OR IGNORE INTO {tn} ({idf}, {cn}) VALUES (targetusername, password)".\
format(tn="Passwords", idf="Username", cn="Password"))
Answer: Use `c.execute()`, not `c.executemany()`, to insert a single row of data. This
is the immediate cause of the error that you experience.
In addition to that, don't use string substitution, use parameterised queries.
Here is a complete working example:
import sqlite3
connection = sqlite3.connect(':memory:') # in memory database
c = connection.cursor()
c.execute('create table Passwords (Username text, Password text)')
targetusername = "user4884072"
password = "$5$rounds=535000$ySH31paWMjEDCUUY$jdrBVGsoYnSMkdVBtjCaxQy2f0g3MX1Wts4vSYz7m.4"
c.execute('insert into Passwords (Username, Password) values (?, ?)', (targetusername, password))
print c.execute('select * from Passwords').fetchall()
Output:
[(u'user4884072', u'$5$rounds=535000$ySH31paWMjEDCUUY$jdrBVGsoYnSMkdVBtjCaxQy2f0g3MX1Wts4vSYz7m.4')]
In the code that you have posted there is no point in substituting values for
the table or column names, so just put them in the query string as shown.
This uses a parameterised query where the API inserts the values for username
and password into the query at the places denoted by `?`. This is safer than
using string substitution because the DB API knows how to properly and safely
escape the values passed to it, and this avoids SQL injection attacks on your
code.
And it uses `execute()` rather than `executemany()` since there is only one
row of data being inserted.
|
PyDAQmx importing confusion
Question: I'm trying to use PyDAQmx. If I try to import like
from PyDAQmx.DAQmxFunctions import *
...
DAQmxResetDevice(ch) #unresolved
the function call is not recognized. However the following works just fine:
import PyDAQmx.DAQmxFunctions as daq
...
daq.DAQmxResetDevice(ch) #fine
Any idea why that might be? I'd like to use the first case just to avoid
unnecessary clutter in my code since there will be a lot of function calls
from that library. I know importing has been discussed to death and I looked
at quite a few threads, but couldn't really find anything explaining my issue.
FYI, python 2.7, PyCharm 4.5.3 Community Edition, NI-DAQ 14.5.1, PyDAQmx
1.3.1.
Answer: PyDAQmx doesn't have an `__all__` definition in its `__init__.py`:
<https://github.com/clade/PyDAQmx/blob/master/PyDAQmx/__init__.py>
Without an `__all__`, Python doesn't know what to
[import](https://docs.python.org/2/tutorial/modules.html#importing-from-a-
package).
|
How to load script when wsadmin shell is used
Question: A system administrator has created a Python script called globalScript. py.
What should the administrator do to ensure globalScript. py is loaded when the
wsadmin shell is used?
A. Compile globalScript.py to a Java class in the bin directory.
B. Invoke wsadmin with the argument-profileName globalScript.py.
C. Modify the configureCustomProperty script to import globalScript. py.
D. D. Set the script profiles in the wsadmin.properties file to load
globalScript .py.
Answer: wsadmin.properties has this entry **com.ibm.ws.scripting.profiles** where we
can add the scripting files to be loaded
So D should be the answer
#-------------------------------------------------------------------------
# The profiles property is a list of profiles to be run before
# running user commands, scripts, or an interactive shell.
# securityProcs is included here by default to make security
# configuration easier.
#-------------------------------------------------------------------------
com.ibm.ws.scripting.profiles=/hosting/products/WebSphereD24/bin/securityProcs.jacl;/hosting/products/WebSphereD24/bin/LTPA_LDAPSecurityProcs.jacl
|
Python loop to get data from every line of file and convert it to dec
Question: I'm kinda lost at the moment: I have text file with lines looking like that:
/dev/input/event0: 0003 0035 000002ac
/dev/input/event0: 0003 0036 000008fb
There are many lines like that, and I want to make script that gets the last
hex value from every line and then writes them in file with output looking
like this:
something someting hex_from_line_1 hex_from_line_2
something someting hex_from_line_3 hex_from_line_4
And so on. As I'm new to Python I have some trouble with making loop which
would do this. Can You give me any guidance? (I'm not asking for whole loop,
only guidance - I'd love to learn that, not use some finished code)
Answer: A fun thing about Python's `zip` is that it will happily take the same
iterator multiple times as arguments, allowing you to pair up inputs easily.
For example:
# For efficiency, if you're on Python 2, include this line so zip is a generator that produces pairs on demand, rather than eagerly slurping the whole file
from future_builtins import zip
with open('myinput') as f:
# Creates a generator that produces only the final space separated value for each line (could be anything; not checking for hex)
final_hex = (line.rsplit(None, 1)[-1] for line in f)
# By using the same generator twice, we get the 1st, 3rd, 5th, etc. from one
# and the 2nd, 4th, 6th, etc. from the other.
for hexa, hexb in zip(final_hex, final_hex):
print("something something", hexa, hexb) # Python 3 print function
print "something something", hexa, hexb # Python 2 print statement
Note: If the input data isn't an even number of lines, this will drop the
final unpaired input. You can use `itertools.zip_longest` (`izip_longest` on
Python 2) if you want the unpaired value.
|
How do I get the current path of the file executing the current thread?
Question: In python, I can do this to get the current file's path:
os.path.dirname(os.path.abspath(__file__))
But if I run this on a thread say:
def do_stuff():
class RunThread(threading.Thread):
def run(self):
print os.path.dirname(os.path.abspath(__file__))
a = RunThread()
a.start()
I get this error:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner
self.run()
File "readrss.py", line 137, in run
print os.path.dirname(os.path.abspath(__file__))
NameError: global name '__file__' is not defined
Answer:
import inspect
print(inspect.stack()[0][1])
[inspect](https://docs.python.org/2/library/inspect.html)
|
Diff output from two commands quickly in vim
Question: I have two hosts that should be running the same version of squid. To verify
that this was indeed true, I ran `squid -v` on each of the hosts and collected
the output from them.
Is there a quick way in vim to compare these text blobs and print the diff? I
was able to do this in python, but was wondering if someone could show me a
few tricks in vim.
host1 # squid3 -v
Squid Cache: Version 3.3.8
Ubuntu
configure options: '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--libexecdir=${prefix}/lib/squid3' '--srcdir=.' '--disable-maintainer-mode' '--disable-dependency-tracking' '--disable-silent-rules' '--datadir=/usr/share/squid3' '--sysconfdir=/etc/squid3' '--mandir=/usr/share/man' '--enable-inline' '--enable-async-io=8' '--enable-storeio=ufs,aufs,diskd,rock' '--enable-removal-policies=lru,heap' '--enable-delay-pools' '--enable-cache-digests' '--enable-underscores' '--enable-icap-client' '--enable-follow-x-forwarded-for' '--enable-auth-basic=DB,fake,getpwnam,LDAP,MSNT,MSNT-multi-domain,NCSA,NIS,PAM,POP3,RADIUS,SASL,SMB' '--enable-auth-digest=file,LDAP' '--enable-auth-negotiate=kerberos,wrapper' '--enable-auth-ntlm=fake,smb_lm' '--enable-external-acl-helpers=file_userip,kerberos_ldap_group,LDAP_group,session,SQL_session,unix_group,wbinfo_group' '--enable-url-rewrite-helpers=fake' '--enable-eui' '--enable-esi' '--enable-icmp' '--enable-zph-qos' '--enable-ecap' '--disable-translation' '--with-swapdir=/var/spool/squid3' '--with-logdir=/var/log/squid3' '--with-pidfile=/var/run/squid3.pid' '--with-filedescriptors=65536' '--with-large-files' '--with-default-user=proxy' '--enable-ssl' '--with-open-ssl=/etc/ssl/openssl.cnf' '--enable-linux-netfilter' 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall' 'LDFLAGS=-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' 'CPPFLAGS=-D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security'
host2 # squid3 -v
Squid Cache: Version 3.3.8
Ubuntu
configure options: '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--libexecdir=${prefix}/lib/squid3' '--srcdir=.' '--disable-maintainer-mode' '--disable-dependency-tracking' '--disable-silent-rules' '--datadir=/usr/share/squid3' '--sysconfdir=/etc/squid3' '--mandir=/usr/share/man' '--enable-inline' '--enable-async-io=8' '--enable-storeio=ufs,aufs,diskd,rock' '--enable-removal-policies=lru,heap' '--enable-delay-pools' '--enable-cache-digests' '--enable-underscores' '--enable-icap-client' '--enable-follow-x-forwarded-for' '--enable-auth-basic=DB,fake,getpwnam,LDAP,MSNT,MSNT-multi-domain,NCSA,NIS,PAM,POP3,RADIUS,SASL,SMB' '--enable-auth-digest=file,LDAP' '--enable-auth-negotiate=kerberos,wrapper' '--enable-auth-ntlm=fake,smb_lm' '--enable-external-acl-helpers=file_userip,kerberos_ldap_group,LDAP_group,session,SQL_session,unix_group,wbinfo_group' '--enable-url-rewrite-helpers=fake' '--enable-eui' '--enable-esi' '--enable-icmp' '--enable-zph-qos' '--enable-ecap' '--disable-translation' '--with-swapdir=/var/spool/squid3' '--with-logdir=/var/log/squid3' '--with-pidfile=/var/run/squid3.pid' '--with-filedescriptors=65536' '--with-large-files' '--with-default-user=proxy' '--enable-linux-netfilter' 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall' 'LDFLAGS=-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' 'CPPFLAGS=-D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security'
I assigned the output from each host to two variables in python and computed
the diff as below:
>>> import re
>>> re.findall("('\S+')", x)
>>> x='''configure options: '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--libexecdir=${prefix}/lib/squid3' '--srcdir=.' '--disable-maintainer-mode' '--disable-dependency-tracking' '--disable-silent-rules' '--datadir=/usr/share/squid3' '--sysconfdir=/etc/squid3' '--mandir=/usr/share/man' '--enable-inline' '--enable-async-io=8' '--enable-storeio=ufs,aufs,diskd,rock' '--enable-removal-policies=lru,heap' '--enable-delay-pools' '--enable-cache-digests' '--enable-underscores' '--enable-icap-client' '--enable-follow-x-forwarded-for' '--enable-auth-basic=DB,fake,getpwnam,LDAP,MSNT,MSNT-multi-domain,NCSA,NIS,PAM,POP3,RADIUS,SASL,SMB' '--enable-auth-digest=file,LDAP' '--enable-auth-negotiate=kerberos,wrapper' '--enable-auth-ntlm=fake,smb_lm' '--enable-external-acl-helpers=file_userip,kerberos_ldap_group,LDAP_group,session,SQL_session,unix_group,wbinfo_group' '--enable-url-rewrite-helpers=fake' '--enable-eui' '--enable-esi' '--enable-icmp' '--enable-zph-qos' '--enable-ecap' '--disable-translation' '--with-swapdir=/var/spool/squid3' '--with-logdir=/var/log/squid3' '--with-pidfile=/var/run/squid3.pid' '--with-filedescriptors=65536' '--with-large-files' '--with-default-user=proxy' '--enable-ssl' '--with-open-ssl=/etc/ssl/openssl.cnf' '--enable-linux-netfilter' 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall' 'LDFLAGS=-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' 'CPPFLAGS=-D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security'
'''
# Similarly, assign output from host2 to x1
>>> s1 = set(re.findall("('\S+')", x))
>>> s2 = set(re.findall("('\S+')", x1))
>>> s1-s2
set(["'--enable-ssl'", "'--with-open-ssl=/etc/ssl/openssl.cnf'"])
Answer: To compare the 2 results you need to get each output in a file on the same
machine (`squid3 -v >> yourFile` and a basic file transfer should do the
trick).
Once you have your two files open them in vim `vim file1 file2`. This will
load both files in vim buffers.
Then you'll need to have two split windows to compare your files: If you are
currently on the `file1` buffer use `:vsplit file2` to open the second buffer
in a vertical split window.
Then you can enter diff mode with `:windo diffthis` and leave it with
`:diffoff`.
As stated by @romanarmy in the comments of your question
[vimcast](http://vimcasts.org/episodes/comparing-buffers-with-vimdiff/) is an
excellent resource to learn more about Vim.
|
Post data as an array in Django Rest Framework
Question: I'm implementing an API using Django Rest framework. I wonder Python can send
POST params as an array like Ruby does?
For example:
POST /api/end_point/
params = { 'user_id': [1,2,3] }
# In controller, we get an array of user_id:
user_ids = params[:user_id] # [1,2,3]
Answer: There are a number of ways to deal with this in `django-rest-framework`,
depending on what you are actually trying to do.
If you are planning on passing this data through `POST` data then you should
use a `Serializer`. Using a serializer and `django-rest-framework`s
`Serializer` you can provide the `POST` data through `json` or through a
`form`.
`Serializer` documentation: <http://www.django-rest-framework.org/api-
guide/serializers/> `Serializer Field` documentation: <http://www.django-rest-
framework.org/api-guide/fields/>
Specifically you will want to look at the `ListField`.
It's not tested, but you will want something along the lines of:
from rest_framework import serializers
from rest_framework.decorators import api_view
class ItemSerializer(serializers.Serializer):
"""Your Custom Serializer"""
# Gets a list of Integers
user_ids = serializers.ListField(child=serializers.IntegerField())
@api_view(['POST'])
def item_list(request):
item_serializer = ItemSerializer(data=request.data)
item_serializer.is_valid(raise_exception=True)
user_ids = item_serializer.data['user_ids']
# etc ...
|
CRITICAL: Unhandled error in Deferred:
Question: I am developing spider project and I have moved to a new computer. Now I am
installing everything and I encounter problem with Twisted. I have read about
this bug and I have installed pywin32 and then also WinPython, but it doesn't
help. I have tried to update Twisted with this command
pip install Twisted --update
as advised in the forum, but it says that pip install doesn't have --update
option. I have also run
python python27\scripts\pywin32_postinstall.py -install
but with no success. This is my error:
G:\Job_vacancies\Python\vacancies>scrapy crawl jobs
2015-10-06 09:12:53 [scrapy] INFO: Scrapy 1.0.3 started (bot: vacancies)
2015-10-06 09:12:53 [scrapy] INFO: Optional features available: ssl, http11
2015-10-06 09:12:53 [scrapy] INFO: Overridden settings: {'NEWSPIDER_MODULE': 'va
cancies.spiders', 'SPIDER_MODULES': ['vacancies.spiders'], 'DEPTH_LIMIT': 3, 'BO
T_NAME': 'vacancies'}
2015-10-06 09:12:53 [scrapy] INFO: Enabled extensions: CloseSpider, TelnetConsol
e, LogStats, CoreStats, SpiderState
Unhandled error in Deferred:
2015-10-06 09:12:53 [twisted] CRITICAL: Unhandled error in Deferred:
Traceback (most recent call last):
File "c:\python27\lib\site-packages\scrapy\cmdline.py", line 150, in _run_comm
and
cmd.run(args, opts)
File "c:\python27\lib\site-packages\scrapy\commands\crawl.py", line 57, in run
self.crawler_process.crawl(spname, **opts.spargs)
File "c:\python27\lib\site-packages\scrapy\crawler.py", line 153, in crawl
d = crawler.crawl(*args, **kwargs)
File "c:\python27\lib\site-packages\twisted\internet\defer.py", line 1274, in
unwindGenerator
return _inlineCallbacks(None, gen, Deferred())
--- <exception caught here> ---
File "c:\python27\lib\site-packages\twisted\internet\defer.py", line 1128, in
_inlineCallbacks
result = g.send(result)
File "c:\python27\lib\site-packages\scrapy\crawler.py", line 71, in crawl
self.engine = self._create_engine()
File "c:\python27\lib\site-packages\scrapy\crawler.py", line 83, in _create_en
gine
return ExecutionEngine(self, lambda _: self.stop())
File "c:\python27\lib\site-packages\scrapy\core\engine.py", line 66, in __init
__
self.downloader = downloader_cls(crawler)
File "c:\python27\lib\site-packages\scrapy\core\downloader\__init__.py", line
65, in __init__
self.handlers = DownloadHandlers(crawler)
File "c:\python27\lib\site-packages\scrapy\core\downloader\handlers\__init__.p
y", line 23, in __init__
cls = load_object(clspath)
File "c:\python27\lib\site-packages\scrapy\utils\misc.py", line 44, in load_ob
ject
mod = import_module(module)
File "c:\python27\lib\importlib\__init__.py", line 37, in import_module
__import__(name)
File "c:\python27\lib\site-packages\scrapy\core\downloader\handlers\s3.py", li
ne 6, in <module>
from .http import HTTPDownloadHandler
File "c:\python27\lib\site-packages\scrapy\core\downloader\handlers\http.py",
line 5, in <module>
from .http11 import HTTP11DownloadHandler as HTTPDownloadHandler
File "c:\python27\lib\site-packages\scrapy\core\downloader\handlers\http11.py"
, line 15, in <module>
from scrapy.xlib.tx import Agent, ProxyAgent, ResponseDone, \
File "c:\python27\lib\site-packages\scrapy\xlib\tx\__init__.py", line 3, in <m
odule>
from twisted.web import client
File "c:\python27\lib\site-packages\twisted\web\client.py", line 42, in <modul
e>
from twisted.internet.endpoints import TCP4ClientEndpoint, SSL4ClientEndpoin
t
File "c:\python27\lib\site-packages\twisted\internet\endpoints.py", line 34, i
n <module>
from twisted.internet.stdio import StandardIO, PipeAddress
File "c:\python27\lib\site-packages\twisted\internet\stdio.py", line 30, in <m
odule>
from twisted.internet import _win32stdio
File "c:\python27\lib\site-packages\twisted\internet\_win32stdio.py", line 7,
in <module>
import win32api
exceptions.ImportError: DLL load failed: The specified module could not be found
.
2015-10-06 09:12:53 [twisted] CRITICAL:
And this is my code:
#!/usr/bin/python
# -*- coding: utf-8 -*-
# encoding=UTF-8
import scrapy, urlparse
from scrapy.http import Request
from scrapy.utils.response import get_base_url
from urlparse import urlparse, urljoin
from vacancies.items import JobItem
#We need that in order to force Slovenian pages instead of English pages. It happened at "http://www.g-gmi.si/gmiweb/" that only English pages were found and no Slovenian.
#from scrapy.conf import settings
#settings.overrides['DEFAULT_REQUEST_HEADERS'] = {'Accept':'text/html,application/xhtml+xml;q=0.9,*/*;q=0.8','Accept-Language':'sl',}
#settings.overrides['DEFAULT_REQUEST_HEADERS'] = {'Accept':'text/html,application/xhtml+xml;q=0.9,*/*;q=0.8','Accept-Language':'sl','en':q=0.8,}
class JobSpider(scrapy.Spider):
name = "jobs"
#Test sample of SLO companies
start_urls = [
"http://www.g-gmi.si/gmiweb/",
]
#Result of the programme is this list of job vacancies webpages.
jobs_urls = []
def parse(self, response):
response.selector.remove_namespaces()
#We take all urls, they are marked by "href". These are either webpages on our website either new websites.
urls = response.xpath('//@href').extract()
#Base url.
base_url = get_base_url(response)
#Loop through all urls on the webpage.
for url in urls:
#If url represents a picture, a document, a compression ... we ignore it. We might have to change that because some companies provide job vacancies information in PDF.
if url.endswith((
#images
'.jpg', '.jpeg', '.png', '.gif', '.eps', '.ico', '.svg', '.tif', '.tiff',
'.JPG', '.JPEG', '.PNG', '.GIF', '.EPS', '.ICO', '.SVG', '.TIF', '.TIFF',
#documents
'.xls', '.ppt', '.doc', '.xlsx', '.pptx', '.docx', '.txt', '.csv', '.pdf', '.pd',
'.XLS', '.PPT', '.DOC', '.XLSX', '.PPTX', '.DOCX', '.TXT', '.CSV', '.PDF', '.PD',
#music and video
'.mp3', '.mp4', '.mpg', '.ai', '.avi', '.swf',
'.MP3', '.MP4', '.MPG', '.AI', '.AVI', '.SWF',
#compressions and other
'.zip', '.rar', '.css', '.flv', '.php',
'.ZIP', '.RAR', '.CSS', '.FLV', '.PHP',
)):
continue
#If url includes characters like ?, %, &, # ... it is LIKELY NOT to be the one we are looking for and we ignore it.
#However in this case we exclude good urls like http://www.mdm.si/company#employment
if any(x in url for x in ['?', '%', '&', '#']):
continue
#Ignore ftp.
if url.startswith("ftp"):
continue
#We need to save original url for xpath, in case we change it later (join it with base_url)
url_xpath = url
#If url doesn't start with "http", it is relative url, and we add base url to get absolute url.
# -- It is true, that we may get some strange urls, but it is fine for now.
if not (url.startswith("http")):
url = urljoin(base_url,url)
#We don't want to go to other websites. We want to stay on our website, so we keep only urls with domain (netloc) of the company we are investigating.
if (urlparse(url).netloc == urlparse(base_url).netloc):
#The main part. We look for webpages, whose urls include one of the employment words as strings.
# -- Instruction.
# -- Users in other languages, please insert employment words in your own language, like jobs, vacancies, career, employment ... --
if any(x in url for x in [
'zaposlovanje',
'Zaposlovanje',
'zaposlitev',
'Zaposlitev',
'zaposlitve',
'Zaposlitve',
'zaposlimo',
'Zaposlimo',
'kariera',
'Kariera',
'delovna-mesta',
'delovna_mesta',
'pridruzi-se',
'pridruzi_se',
'prijava-za-delo',
'prijava_za_delo',
'oglas',
'Oglas',
'iscemo',
'Iscemo',
'careers',
'Careers',
'jobs',
'Jobs',
'employment',
'Employment',
]):
#This is additional filter, suggested by Dan Wu, to improve accuracy. We will check the text of the url as well.
texts = response.xpath('//a[@href="%s"]/text()' % url_xpath).extract()
#1. Texts are empty.
if texts == []:
print "Ni teksta za url: " + str(url)
#We found url that includes one of the magic words and also the text includes a magic word.
#We check url, if we have found it before. If it is new, we add it to the list "jobs_urls".
if url not in self.jobs_urls:
self.jobs_urls.append(url)
item = JobItem()
#item["text"] = text
item["url"] = url
#We return the item.
yield item
# 2. There are texts, one or more.
else:
#For the same partial url several texts are possible.
for text in texts:
if any(x in text for x in [
'zaposlovanje',
'Zaposlovanje',
'zaposlitev',
'Zaposlitev',
'zaposlitve',
'Zaposlitve',
'zaposlimo',
'Zaposlimo',
'ZAPOSLIMO',
'kariera',
'Kariera',
'delovna-mesta',
'delovna_mesta',
'pridruzi-se',
'pridruzi_se',
'oglas',
'Oglas',
'iscemo',
'Iscemo',
'ISCEMO',
'careers',
'Careers',
'jobs',
'Jobs',
'employment',
'Employment',
]):
#We found url that includes one of the magic words and also the text includes a magic word.
#We check url, if we have found it before. If it is new, we add it to the list "jobs_urls".
if url not in self.jobs_urls:
self.jobs_urls.append(url)
item = JobItem()
item["text"] = text
item["url"] = url
#We return the item.
yield item
#We don't put "else" sentence because we want to further explore the employment webpage to find possible new employment webpages.
#We keep looking for employment webpages, until we reach the DEPTH, that we have set in settings.py.
yield Request(url, callback = self.parse)
# We run the programme in the command line with this command:
# scrapy crawl jobs -o jobs.csv -t csv --logfile log.txt
# We get two output files
# 1) jobs.csv
# 2) log.txt
# Then we manually put one of employment urls from jobs.csv into read.py
I would be glad if you could give some advice on how to run this thing. Thank
you, Marko
Answer: You should always install stuff into a
[virtualenv](http://virtualenv.readthedocs.org/en/latest/). Once you've got a
virtualenv and it's active, do:
pip install --upgrade twisted pypiwin32
and you should get the depenendency that makes Twisted support stdio on the
Windows platform.
To get _all_ the goodies you might try
pip install --upgrade twisted[windows_platform]
but you may run into problems with `gmp.h` if you try that, and you don't need
most of it to do what you're trying to do.
|
How to extend the space for y ticks in barh - python matplotlib
Question: Please see attached image
[](http://i.stack.imgur.com/gL2A0.jpg)
I have the source code as follows in python
def plotBarChartH(self,data):
LogManager.logDebug('Executing Plotter.plotBarChartH')
if type(data) is not dict:
LogManager.logError('Input data parameter is not in right format. Need a dict')
return False
testNames = []
testTimes = []
for val in data:
testNames.append(val)
testTimes.append(data[val])
matplotlib.rcParams.update({'font.size': 8})
yPos = np.arange(len(testNames))
plt.barh(yPos, testTimes, height=0.4, align='center', alpha=0.4)
plt.yticks(yPos, testNames)
plt.xlabel('time (seconds)')
plt.title('Test Execution Times')
savePath = os.path.join(ConfigurationManager.applicationConfig['robotreportspath'],'bar.jpg')
plt.savefig(savePath)
plt.clf()
return True
The bar looks fine but I have two issues
1. How can the text in y-axis can be shown in full? I mean some text are cut-off and i want to extend the space in occupies so that it can be displayed in full.
2. Can I Increase the whole plot area on which the charts are drawn? I want to increase the width of of plot area so that image looks bit bigger
thanks
Answer: You can set the figure size (in inches) explicitly when you create a `Figure`
object with `plt.figure(figsize=(width,height)), and call`plt.tight_layout()`
to make room for your tick labels as follows:
import matplotlib.pyplot as plt
names = ['Content Channels','Kittens for Xbox Platform','Tigers for PS Platform',
'Content Series', 'Wombats for Mobile Platform']
values = [260, 255, 420, 300, 270]
fig = plt.figure(figsize=(10,4))
ax = fig.add_subplot(111)
yvals = range(len(names))
ax.barh(yvals, values, align='center', alpha=0.4)
plt.yticks(yvals,names)
plt.tight_layout()
plt.show()
[](http://i.stack.imgur.com/PYiI8.png)
|
Run Python script from another and pass the variables and output
Question: When looking for a tutorial on passing variables and output between Python
scripts I couldn't find any example that would work with the WSGI Server in my
example.
I want the **output (and variables)** returned in HTML instead of seeing it
only in the console.
The best solution for calling python script from another I found is
**subprocess** , but I still can't see the merged output of Script 1 and
Script 2 of in my web browser and only in console.
Script 1:
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
from cgi import escape
import sys, os
from flup.server.fcgi import WSGIServer
import subprocess
def app(environ, start_response):
start_response('200 OK', [('Content-Type', 'text/html')])
yield '<h1>Test - Python pass output and variables</h1>'
yield '<p>Script 1</p>'
yield subprocess.check_output(["python", "script2.py"])
WSGIServer(app).run()
Script 2:
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
print "<p>Script 2</p>";
Answer: If you want to pass variables between scripts in python, do something like
this:
Script1.py:
def passVars():
variable = "bla"
return variable
Script2.py:
import Script1 as sc1
var = sc1.passVars()
|
Validating Log In funtionality in website using Selenium webdriver with Python
Question: I am trying to click the "Log In" element present in webpage. "Log In" element
is visible , when you click on ACCOUNT element on website.
code is :
import unittest
from selenium import webdriver
class registernewuser(unittest.TestCase):
@classmethod
def setUpClass(cls):
cls.driver = webdriver.Chrome()
cls.driver.implicitly_wait(10)
cls.driver.maximize_window()
cls.driver.get("http://demo.magentocommerce.com/")
def test_register_new_user(self):
driver = self.driver
account_click = driver.find_element_by_link_text("ACCOUNT").click()
driver.implicitly_wait(3)
self.driver.find_element_by_link_text('Log In').click()
@classmethod
def tearDownClass(cls):
cls.driver.quit()
Answer: Added [account_click = driver.find_element_by_link_text("ACCOUNT").click()
driver.implicitly_wait(3) ] in code and it worked . If you want to click an
element which is a part of dropdown of main element , click main element-->
implicitily wait command ---> Click dropdown element.
|
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