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Python: Transform a unicode variable into a string variable
Question: I used a web crawler to get some data. I stored the data in a variable
`price`. The type of `price` is:
<class 'bs4.element.NavigableString'>
The type of each element of `price` is:
<type 'unicode'>
Basically the `price` contains some white space and line feeds followed by:
`$520`. I want to eliminate all the extra symbols and recover only the number
`520`. I already did a naive solution:
def reducePrice(price):
key=0
string=""
for i in price:
if (key==1):
string=string+i
if (i== '$'):
key=1
key=0
return string
But I want to implement a more elegant solution, transforming the type of
`price` into `str` and then using `str` methods to manipulate it. I already
searched a lot in the web and other posts in the forum. The best I could get
was that using:
p = "".join(price)
I can generate a big unicode variable. If you can give me a hint I would be
grateful (I'm using python 2.7 in Ubuntu).
**edit** I add my spider just in case you need it:
def spider(max_pages):
page = 1
while page <= max_pages:
url = "http://www.lider.cl/walmart/catalog/product/productDetails.jsp?cId=CF_Nivel2_000021&productId=PROD_5913&skuId=5913&pId=CF_Nivel1_000004&navAction=jump&navCount=12"
source_code = requests.get(url)
plain_text = source_code.text
soup = BeautifulSoup(plain_text)
title = ""
price = ""
for link in soup.findAll('span', {'itemprop': 'name'}):
title = link.string
for link in soup.find('em', {'class': 'oferLowPrice fixPriceOferUp '}):
price = link.string
print(title + '='+ str(reducePrice(price)))
page += 1
spider(1)
**edit 2** Thanks to Martin and mASOUD I could generate the solution using
`str` methods:
def reducePrice(price):
return int((("".join(("".join(price)).split())).replace("$","")).encode())
This method return an `int`. This was not my original question but it was the
next step in my project. I added it because we can't cast unicode into `int`
but using encode() to generate a `str` first, we can.
Answer: Use a RegEx to extract the price from your Unicode string:
import re
def reducePrice(price):
match = re.search(r'\d+', u' $500 ')
price = match.group() # returns u"500"
price = str(price) # convert "500" in unicode to single-byte characters.
return price
Even though this function converts Unicode to a "regular" string as you asked,
is there any reason you want this? Unicode strings can be worked with the same
way as a regular string. That is `u"500"` is almost the same as `"500"`
|
Find Pandas dataframe column based on values, in Python
Question: I have 2 Pandas Dataframes in Python. Here they are:
import numpy as np
import pandas as pd
df = pd.DataFrame(np.random.rand(10,3),columns=list('ABC'))
df2 = pd.DataFrame(np.random.rand(10,3),columns=list('ABC'))
df['A'] = 1
print df
print df2
A B C
0 1 0.333141 0.803991
1 1 0.043958 0.582038
2 1 0.833433 0.782856
3 1 0.722592 0.237912
4 1 0.634979 0.664208
5 1 0.809748 0.889524
6 1 0.110342 0.650617
7 1 0.035417 0.251089
8 1 0.481492 0.128792
9 1 0.190135 0.213608
A B C
0 0.897373 0.599721 0.361668
1 0.495024 0.471351 0.090395
2 0.651174 0.621328 0.721208
3 0.253459 0.567619 0.104370
4 0.357627 0.616717 0.775327
5 0.164323 0.716166 0.740565
6 0.841509 0.464837 0.398952
7 0.398680 0.186555 0.293076
8 0.298785 0.784237 0.704184
9 0.124763 0.384852 0.307361
As you can see in `df`, there is one column with **only** 1's.
I need to do the following:
1. Find the name of the column in a Dataframe (`df`) that contains **only** 1's in all rows.
2. Drop that column from `df`
3. Drop that **SAME** column from `df2`
I would like to get this:
B C
0 0.333141 0.803991
1 0.043958 0.582038
2 0.833433 0.782856
3 0.722592 0.237912
4 0.634979 0.664208
5 0.809748 0.889524
6 0.110342 0.650617
7 0.035417 0.251089
8 0.481492 0.128792
9 0.190135 0.213608
B C
0 0.599721 0.361668
1 0.471351 0.090395
2 0.621328 0.721208
3 0.567619 0.104370
4 0.616717 0.775327
5 0.716166 0.740565
6 0.464837 0.398952
7 0.186555 0.293076
8 0.784237 0.704184
9 0.384852 0.307361
Is there a way to do this?
Answer: You can use `DataFrame.apply` with `axis=0` to apply a function to every
column of a dataframe. In your case you want to check whether `all(col==1)`
for each column. Then you can pick out the columns using a list comprehension,
and finally use `DataFrame.drop` do drop the columns:
allonecols = df.apply(lambda col: all(col==1), axis = 0)
allonecols
A True
B False
C False
dtype: bool
dropcols = [k for k,v in allonecols.to_dict().items() if v]
dropcols
['A']
df2.drop(dropcols, axis = 1)
|
Python: generating a "curve fit score"
Question: I am working on a project in which I am trying to model the movement of an
object in a [kymograph](http://en.wikipedia.org/wiki/Kymograph). In order to
do so, I fit a curve to each line of pixels in an image, and append the
location of the vertex to approximately model the location of the object in
the image. Below is a sample image.
As you can see, early in the time series (at the top of the image) the
position of the object is nicely focused and easily modeled with a Gaussian
curve. However, closer to the end of the time series (at the bottom of the
image), the peak is much more diffuse. I suspect that the data at the bottom
of the image will be fit much more closely by a curve modeling a Poisson
distribution (image below, right) while the data at the top/middle of the
image will be fit much more closely by a Gaussian or polynomial curve (image
below, left).
Is there any way to, for each line of pixels, fit more than one curve to the
same data and then score each for a least-squares fit? This way, I could
(hopefully) switch models midway through an image to accommodate changing
behaviors of the object that I am trying to track. My current code is below:
from PIL import Image
def populateData(picture) :
"""Open an image and populate a list of lists with the grayscale value"""
im = Image.open(picture)
size = im.size
width = size[0]
height = size[1]
allPixels = list(im.getdata())
pixelList = [allPixels[width*i :
width * (i+1)] for i in range(height)]
return(pixelList)
rawData = populateData("testTop.tif")
import numpy as np
from scipy.optimize import curve_fit
def findVertex(listOfRows) :
xList = []
for row in listOfRows :
x = np.arange(len(row))
ffunc = lambda x, a, x0, s: a*np.exp(-0.5*(x-x0)**2/s**2)
p, _ = curve_fit(ffunc, x, row, p0=[100,5,2])
x0 = p[1]
xList.append(x0)
xArray = np.array(xList)
return(xArray)
xValues = findVertex(rawData)
def buildRows(listOfRows) :
yArray = np.arange(len(listOfRows))
return(yArray)
yValues = buildRows(rawData)
from matplotlib import pyplot as plt
from scipy import ndimage
image = ndimage.imread("testTop.tif",flatten=True)
fig = plt.figure()
axes = fig.add_subplot(111)
axes.imshow(image)
axes.plot(xValues, yValues, 'k-')
axes.set_title('testLine')
axes.grid()
axes.set_xlabel('x')
axes.set_ylabel('time')
plt.show()
EDIT: This is the file I used as an input (testTop.tif) 
Answer: You will need to work out some form of [goodness of
fit](http://en.wikipedia.org/wiki/Goodness_of_fit) between the fit and your
data. Taking the sum of the squared differences between your current fit (a
Gaussian) and your data divided by the variance.
sumerrsq = 0.
for i in range(yValues.shape[0]):
sumerrsq += np.power(yValues[i] - xValues[i],2)
goodfit = np.sqrt(sumerrsq/var)
I think you can use use the second output from curve fit (the covariance) to
get the variance,
p, pcov = curve_fit(ffunc, x, row, p0=[100,5,2])
var = np.diag(pcov)
You can then check the value of goodfit and if it is not sufficient, switch to
a different distribution. In using a different distribution, you may need to
use a different estimation of error (this assumes the errors are normally
distributed).
Note, without the data (and not being sure what array was which) I couldn't
test any of this code...
|
Numba : 'Module' object has no attribute 'global_variables'
Question: This is a basic example of numba
import numpy as np
from numba import double
from numba.decorators import jit, autojit
X = np.random.random((1000, 3))
def pairwise_python(X):
M = X.shape[0]
N = X.shape[1]
D = np.empty((M, M), dtype=np.float)
for i in range(M):
for j in range(M):
d = 0.0
for k in range(N):
tmp = X[i, k] - X[j, k]
d += tmp*tmp
D[i, j] = np.sqrt(d)
return D
pairwise_numba = autojit(pairwise_python)
pairwise_numba(X)
But it generate the error message
AttributeError: Failed at object (object mode frontend)
Failed at object (object mode backend)
'Module' object has no attribute 'global_variables'
My conda version is
numba 0.18.2 np19py27_1
numbapro 0.18.0 np19py27_p2
llvmlite 0.4.0 py27_0
Do you have a same problem? Help me..
Answer: It's complicated. This is my solution.
$ sudo apt-get install llvm-3.5-dev
$ sudo apt-get install libedit-dev
$ pip install enum34
$ git clone https://github.com/numba/llvmlite
$ cd llvmlite
$ LLVM_CONFIG=/usr/bin/llvm-config-3.5 python setup.py install
$ conda install numba
Fetching package metadata: ....
Solving package specifications: .
Package plan for installation in environment /home/khkim/anaconda/envs/test:
The following packages will be UPDATED:
numba: 0.17.0-np19py27_0 --> 0.18.2-np19py27_1
The following packages will be DOWNGRADED:
llvmlite: 0.5.0-py27_0 --> 0.4.0-py27_0
And the code work well.
|
Replace a particular text from a CSV file without knowing the text
Question: I need to replace a particular value from a text file, without knowing the
value of the string to be replaced. All I know is the line number, and the
location of the value in that line which has to be replaced. This has to be
done using Python 2.7
for example, the file is like this:
a,b,c,s,d,f
s,d,f,g,d,f
a,d,s,f,g,r
a,s,d,f,e,c
My code goes like this:
point_file = open(pointfile,'r+')
read_lines = point_file.readlines()
arr1 = []
for i in range(len(read_lines)):
arr1.append(read_lines[i])
Now I need to replace
arr1[3].split(',')[3]
How to do that?
**Edit**
I do not wish to achieve this using a temporary copy file and then overwrite
the existing file. I need to edit the value **in place** the **existing**
file.
Answer: OK, so I'm assuming fields can have any value (or the following can be
shortened considerably by clever substitution tricks).
from __future__ import print_function
target = (3, 3) # Coordinates of the replaced value
new_val = 'X' # New value for the replaced cells
with open('src.txt') as f_src:
data = f_src.read().strip()
table = [line.split(',') for line in data.split('\n')]
old_val = table[target[0]][target[1]]
new_data = '\n'.join(
','.join(
new_val if cell == old_val else cell
for cell in row)
for row in table)
with open('tgt.txt', 'w') as f_tgt:
print(new_data, file=f_tgt)
My test `src.txt`:
a,b,c,s,d,f
s,d,f,g,d,f
a,d,s,f,g,r
a,s,d,f,e,c
My output `tgt.txt`:
a,b,c,s,d,X
s,d,X,g,d,X
a,d,s,X,g,r
a,s,d,X,e,c
|
Parsing XML with undeclared prefixes in Python
Question: I am trying to parse XML data with Python that uses prefixes, but not every
file has the declaration of the prefix. Example XML:
<?xml version="1.0" encoding="UTF-8"?>
<item subtype="bla">
<thing>Word</thing>
<abc:thing2>Another Word</abc:thing2>
</item>
I have been using xml.etree.ElementTree to parse these files, but whenever the
prefix is not properly declared, ElementTree throws a parse error. (`unbound
prefix`, right at the start of `<abc:thing2>`) Searching for this error leads
me to solutions that suggest I fix the namespace declaration. However, I do
not control the XML that I need to work with, so modifying the input files is
not a viable option.
Searching for namespace parsing in general leads me to many questions about
searching in namespace-agnostic way, which is not what I need.
I am looking for some way to automatically parse these files, even if the
namespace declaration is broken. I have thought about doing the following:
* tell ElementTree what namespaces to expect beforehand, because I do know which ones can occur. I found `register_namespace`, but that does not seem to work.
* have the full DTD read in before parsing, and see if that solves it. I could not find a way to do this with ElementTree.
* tell ElementTree to not bother about namespaces at all. It should not cause issues with my data, but I found no way to do this
* use some other parsing library that _can_ handle this issue - though I prefer not to need installation of extra libraries. I have difficulty seeing from the documentation if any others would be able to solve my issue.
* some other route that I am currently not seeing?
UPDATE: After Har07 put me on the path of `lxml`, I tried to see if this would
let me perform the different solutions I had thought of, and what the result
would be:
* telling the parser what namespaces to expect beforehand: I still could not find any 'official' way to do this, but in my searches before I had found the suggestion to simply add the requisite declaration to the data programmatically. (for a different programming situation - unfortunately I can't find the link anymore) It seemed terribly hacky to me, but I tried it anyway. It involves loading the data as a string, changing the enclosing element to have the right `xmlns` declarations, and then handing it off to `lxml.etree`'s `fromstring` method. Unfortunately, that also requires removing all reference to encoding declaration from the string. It works, though.
* Read in the DTD before parsing: it is possible with `lxml` (through `attribute_defaults`, `dtd_validation`, or `load_dtd`), but unfortunately does not solve the namespace issue.
* Telling `lxml` not to bother about namespaces: possible through the `recover` option. Unfortunately, that also ignores other ways in which the XML may be broken (see Har07's answer for details)
Answer: One possible way is using `ElementTree` compatible library,
[`lxml`](http://lxml.de/compatibility.html). For example :
from lxml import etree as ElementTree
xml = """<?xml version="1.0" encoding="UTF-8"?>
<item subtype="bla">
<thing>Word</thing>
<abc:thing2>Another Word</abc:thing2>
</item>"""
parser = ElementTree.XMLParser(recover=True)
tree = ElementTree.fromstring(xml, parser)
thing = tree.xpath("//thing")[0]
print(ElementTree.tostring(thing))
All you need to do for parsing a non well-formed XML using `lxml` is passing
parameter `recover=True` to constructor of `XMLParser`. `lxml` also has full
support for xpath 1.0 which is very useful when you need to get part of XML
document using more complex criteria.
**UPDATE :**
I don't know all the types of XML error that `recover=True` option can
tolerate. But here is another type of error that I know besides unbound
namespace prefix: unclosed tag. `lxml` will fix -rather than ignore- unclosed
tag by adding corresponding closing tag automatically. For example, given the
following broken XML :
xml = """<item subtype="bla">
<thing>Word</thing>
<bad>
<abc:thing2>Another Word</abc:thing2>
</item>"""
parser = ElementTree.XMLParser(recover=True)
tree = ElementTree.fromstring(xml, parser)
print(ElementTree.tostring(tree))
The final output XML after parsed by `lxml` is as follow :
<item subtype="bla">
<thing>Word</thing>
<bad>
<abc:thing2>Another Word</abc:thing2>
</bad></item>
|
UnicodeDecodeError: 'charmap' codec can't decode byte 0x8d in position 7240: character maps to <undefined>
Question: I am student doing my master thesis. As part of my thesis, I am working with
**python**. I am reading a log file of `.csv` format and writing the extracted
data to another `.csv` file in a well formatted way. However, when the file is
read, I am getting this error:
> Traceback (most recent call last): File
> "C:\Users\SGADI\workspace\DAB_Trace\my_code\trace_parcer.py", line 19, in
> for row in reader:
>
> * File
> "C:\Users\SGADI\Desktop\Python-32bit-3.4.3.2\python-3.4.3\lib\encodings\cp1252.py",
> line 23, in decode return
> `codecs.charmap_decode(input,self.errors,decoding_table)[0]`
> * UnicodeDecodeError: 'charmap' codec can't decode byte 0x8d in position
> 7240: character maps to `<undefined>`
>
import csv
import re
#import matplotlib
#import matplotlib.pyplot as plt
import datetime
#import pandas
#from dateutil.parser import parse
#def parse_csv_file():
timestamp = datetime.datetime.strptime('00:00:00.000', '%H:%M:%S.%f')
timestamp_list = []
snr_list = []
freq_list = []
rssi_list = []
dab_present_list = []
counter = 0
f = open("output.txt","w")
with open('test_log_20150325_gps.csv') as csvfile:
reader = csv.reader(csvfile, delimiter=';')
for row in reader:
#timestamp = datetime.datetime.strptime(row[0], '%M:%S.%f')
#timestamp.split(" ",1)
timestamp = row[0]
timestamp_list.append(timestamp)
#timestamp = row[0]
details = row[-1]
counter += 1
print (counter)
#if(counter > 25000):
# break
#timestamp = datetime.datetime.strptime(row[0], '%M:%S.%f')
#timestamp_list.append(float(timestamp))
#search for SNRLevel=\d+
snr = re.findall('SNRLevel=(\d+)', details)
if snr == []:
snr = 0
else:
snr = snr[0]
snr_list.append(int(snr))
#search for Frequency=09ABC
freq = re.findall('Frequency=([0-9a-fA-F]+)', details)
if freq == []:
freq = 0
else:
freq = int(freq[0], 16)
freq_list.append(int(freq))
#search for RSSI=\d+
rssi = re.findall('RSSI=(\d+)', details)
if rssi == []:
rssi = 0
else:
rssi = rssi[0]
rssi_list.append(int(rssi))
#search for DABSignalPresent=\d+
dab_present = re.findall('DABSignalPresent=(\d+)', details)
if dab_present== []:
dab_present = 0
else:
dab_present = dab_present[0]
dab_present_list.append(int(dab_present))
f.write(str(timestamp) + "\t")
f.write(str(freq) + "\t")
f.write(str(snr) + "\t")
f.write(str(rssi) + "\t")
f.write(str(dab_present) + "\n")
print (timestamp, freq, snr, rssi, dab_present)
#print (index+1)
#print(timestamp,freq,snr)
#print (counter)
#print(timestamp_list,freq_list,snr_list,rssi_list)
'''if snr != []:
if freq != []:
timestamp_list.append(timestamp)
snr_list.append(snr)
freq_list.append(freq)
f.write(str(timestamp_list) + "\t")
f.write(str(freq_list) + "\t")
f.write(str(snr_list) + "\n")
print(timestamp_list,freq_list,snr_list)'''
f.close()
I searched for the special character and I did not find any. I searched the
Internet which suggested to change the format: I tried ut8, latin1 and few
other formats, but i am still getting this error. Can you please help me how
to solve with `pandas` as well. I also tried with `pandas` but I am still
getting the error. I even removed a line in the log file, but the error occurs
in the next line.
Please help me finding a solution, thank you.
Answer: i have solved this issue. we can use this code
import codecs
types_of_encoding = ["utf8", "cp1252"]
for encoding_type in types_of_encoding:
with codecs.open(filename, encoding = encoding_type, errors ='replace') as csvfile:
your code
....
....
|
Building libxml with gradle
Question: Could you please share your wisdom on cross-compilation of a library like
`libxml2`, `libpng`, `libfreetype` that has a configure script and a Makefile
for android and other hosts like linux, windows and Mac Os X using **gradle**?
At the moment I do not have a complete working example for either libraries
but would like to have a solution similar to the following:
<https://github.com/couchbase/couchbase-lite-java-
native/blob/master/crosscompile-build.gradle>
//
// To cross compile to ARM replace the default build.gradle with this file.
// Before running the build install these additional linux packages
//
// gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf
//
apply plugin: 'c'
apply plugin: 'java'
apply plugin: 'maven'
version = System.getenv("MAVEN_UPLOAD_VERSION")
model {
platforms {
osx_x86 {
architecture "x86"
operatingSystem "osx"
}
osx_x86_64 {
architecture "x86_64"
operatingSystem "osx"
}
linux_x86 {
architecture "x86"
operatingSystem "linux"
}
linux_x86_64 {
architecture "x86_64"
operatingSystem "linux"
}
linux_amd64 {
architecture "amd64"
operatingSystem "linux"
}
linux_arm {
architecture "arm"
operatingSystem "linux"
}
windows_x86 {
architecture "x86"
operatingSystem "windows"
}
windows_x86_64 {
architecture "x86_64"
operatingSystem "windows"
}
windows_amd64 {
architecture "amd64"
operatingSystem "windows"
}
}
toolChains {
visualCpp(VisualCpp)
gcc(Gcc)
gccArm(Gcc) {
getCppCompiler().setExecutable 'arm-linux-gnueabihf-g++'
getCCompiler().setExecutable 'arm-linux-gnueabihf-gcc'
getAssembler().setExecutable 'arm-linux-gnueabihf-as'
getLinker().setExecutable 'arm-linux-gnueabihf-gcc'
getStaticLibArchiver().setExecutable 'arm-linux-gnueabihf-ar'
addPlatformConfiguration(new ArmSupport())
}
clang(Clang)
}
}
class ArmSupport implements TargetPlatformConfiguration {
boolean supportsPlatform(Platform element) {
return element.getArchitecture().name == "arm"
}
List<String> getCppCompilerArgs() {
[]
}
List<String> getObjectiveCppCompilerArgs() {
[]
}
List<String> getObjectiveCCompilerArgs() {
[]
}
List<String> getCCompilerArgs() {
[]
}
List<String> getAssemblerArgs() {
[]
}
List<String> getLinkerArgs() {
[]
}
List<String> getStaticLibraryArchiverArgs() {
[]
}
}
sources {
native_library {
c {
source {
srcDir "src/main/c"
}
exportedHeaders {
srcDir "src/main/include"
}
}
}
}
libraries {
native_library {
baseName "CouchbaseLiteJavaNative"
}
all {
binaries.withType(SharedLibraryBinary) { binary ->
if (targetPlatform.operatingSystem.macOsX) {
cCompiler.args '-I', "/System/Library/Frameworks/JavaVM.framework/Headers"
linker.args '-framework', "JavaVM"
} else if (targetPlatform.operatingSystem.linux) {
cCompiler.args '-I', "${org.gradle.internal.jvm.Jvm.current().javaHome}/include"
cCompiler.args '-I', "${org.gradle.internal.jvm.Jvm.current().javaHome}/include/linux"
} else if (targetPlatform.operatingSystem.windows) {
cCompiler.args "-I${org.gradle.internal.jvm.Jvm.current().javaHome}/include"
cCompiler.args "-I${org.gradle.internal.jvm.Jvm.current().javaHome}/include/win32"
linker.args "--add-stdcall-alias"
}
}
}
}
binaries.withType(SharedLibraryBinary) { binary ->
if (!buildable) {
return
}
def builderTask = binary.tasks.builder
jar.into("native/${targetPlatform.operatingSystem.name}/${targetPlatform.architecture.name}") {
from builderTask.outputFile
}
jar.dependsOn builderTask
}
task createMavenDirectory(type: Exec) {
ext {
uploadUser = System.getenv("MAVEN_UPLOAD_USERNAME") + ":" + System.getenv("MAVEN_UPLOAD_PASSWORD")
mkcolPath = System.getenv("MAVEN_UPLOAD_REPO_URL") + "com/couchbase/lite/java-native/" + version + "/"
}
commandLine "curl", "--user", uploadUser, "-X", "MKCOL", mkcolPath
}
// this hack is only needed for apache mod_dav based Maven repo's like file.couchbase.com. otherwise, skip it
createMavenDirectory.onlyIf { System.getenv("MAVEN_UPLOAD_REPO_URL").contains("files") }
// first create the directory, then do the upload
task uploadArchivesWrapper(dependsOn: createMavenDirectory) << {
uploadArchives.execute()
}
// this will upload, but will not first create a directory (which is needed on some servers)
uploadArchives {
repositories {
mavenDeployer {
repository(url: System.getenv("MAVEN_UPLOAD_REPO_URL")) {
authentication(userName: System.getenv("MAVEN_UPLOAD_USERNAME"), password: System.getenv("MAVEN_UPLOAD_PASSWORD"))
}
pom.version = version
pom.groupId = 'com.couchbase.lite'
pom.artifactId = 'java-native'
pom.project {
licenses {
license {
name 'Couchbase Community Edition License Agreement'
url 'http://www.couchbase.com/agreement/community'
distribution 'repo'
}
}
}
}
}
}
task sourcesJar(type: Jar, dependsOn: classes) {
classifier = 'sources'
from sourceSets.main.java.srcDirs
}
artifacts {
archives sourcesJar
}
It would be ideal to use the toolchain provided by **Android NDK** and not
specify **gnueabi** and link everything statically.
## Edit
I have extended the build file quite a bit, however I am getting `UP-TO DATE`
for all of the tasks:
The setup is: `libxml2-2.9.2`
`build.gradle`
apply plugin: 'c'
import com.ulabs.gradle.AutoConfigureTask
import com.ulabs.gradle.MakefileTask
import com.ulabs.gradle.ConfigureTask
gradle.allprojects {
ext.getLibXmlLibsPath = {
def distDir = new File(project(":libxml2").projectDir, "buildLibxml2")
return distDir.toString()
}
ext.getLibXmlHeaderPath = {
def hDir = new File(project(":libxml2").projectDir, "include")
return hDir.toString()
}
}
project(':libxml2') {
model {
toolChains {
visualCpp(VisualCpp)
gcc(Gcc)
clang(Clang)
}
platforms {
x86 {
architecture "x86"
}
x64 {
architecture "x86_64"
}
itanium {
architecture "ia-64"
}
}
components {
xml2(NativeLibrarySpec) {
sources {
c {
exportedHeaders {
srcDir "include"
include "libxml/*.h"
}
exportedHeaders {
srcDir "include"
include "win32config.h", "wsockcompat.h"
}
exportedHeaders {
srcDir "."
include "libxml.h"
}
}
}
}
}
repositories {
libs(PrebuiltLibraries) {
libxml2 {
headers.srcDir getLibXmlHeaderPath()
binaries.withType(StaticLibraryBinary) {
def baseDir = getLibXmlLibsPath()
staticLibraryFile = file("${baseDir}/libxml2.a")
}
binaries.withType(SharedLibraryBinary) {
def os = targetPlatform.operatingSystem
def baseDir = getLibXmlLibsPath()
if (os.windows) {
sharedLibraryFile = file("${baseDir}/libxml2.dll")
if (file("${baseDir}/util.lib").exists()) {
sharedLibraryLinkFile = file("${baseDir}/libxml2.lib")
}
} else if (os.macOsX) {
sharedLibraryFile = file("${baseDir}/libxml2.dylib")
} else {
sharedLibraryFile = file("${baseDir}/libxml2.so")
}
}
}
}
}
}
task autoConfigTask(type: AutoConfigureTask) << {
extraArgs ""
}
task configureTask(type: ConfigureTask, dependsOn: autoConfigTask) << {
extraArgs "--without-python", "--without-zlib"
}
task makeFileTask(type: MakefileTask, dependsOn: configureTask) << {
println "Running makefile Task ${project}"
}
task make(dependsOn : makeFileTask) << {
def distDir = new File(getLibXmlLibsPath())
delete distDir.toString()
distDir.mkdirs()
def binDir = projectDir.toString() + "/.libs"
FileTree tree = fileTree(binDir.toString()) {
include 'libxml2*'
exclude '*.la*'
}
tree.each {File file ->
copy {
from file.toString()
into distDir.toString()
}
}
}
}
build.dependsOn(make)
assemble.dependsOn(make)
`buildSrc/src/main/groovy/com/ulabs/gradle/*.groovy` contains:
package com.ulabs.gradle
import org.gradle.api.DefaultTask
import org.gradle.api.tasks.TaskAction
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.Optional
import org.gradle.api.Project
import org.gradle.api.tasks.incremental.IncrementalTaskInputs
class AutoConfigureTask extends DefaultTask {
@Input
@Optional
def extraArgs
@TaskAction
def execConfigure(IncrementalTaskInputs inputs) {
println "Launching AutoConfigureTask from: " + project.projectDir
if(!new File(project.projectDir, 'configure.ac').exists() &&
!new File(project.projectDir, 'configure.in').exists()) {
throw new FileNotFoundException(
'autoconfigure task should have either configure.in or configure.ac ')
}
boolean outDated = false
inputs.outOfDate { change ->
outDated = true
}
if(outDated) {
project.exec {
executable "autoreconf"
args "-ivf", hasProperty("extraArgs") ? extraArgs : ""
}
}
}
}
package com.ulabs.gradle
import org.gradle.api.DefaultTask
import org.gradle.api.tasks.TaskAction
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.Optional
import org.gradle.api.Project
import org.gradle.api.tasks.incremental.IncrementalTaskInputs
class ConfigureTask extends DefaultTask {
@Input
@Optional
def extraArgs
@TaskAction
def execConfigure(IncrementalTaskInputs inputs) {
if(!new File(project.projectDir, 'configure').exists()) {
throw new FileNotFoundException(
'configure task should have a configure script')
}
boolean outDated = false
inputs.outOfDate { change ->
outDated = true
}
if(outDated) {
project.exec {
executable "./configure"
args hasProperty("extraArgs") ? extraArgs : ""
}
}
}
}
package com.ulabs.gradle
import org.gradle.api.DefaultTask
import org.gradle.api.tasks.TaskAction
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.Optional
import org.gradle.api.Project
import org.gradle.api.tasks.incremental.IncrementalTaskInputs
class MakefileTask extends DefaultTask {
@Input
@Optional
def extraArgs
@Input
@Optional
def env
@TaskAction
def execConfigure(IncrementalTaskInputs inputs) {
if(!new File(project.projectDir, 'configure').exists()) {
throw new FileNotFoundException(
'makefile task should have a Makefile script')
}
boolean outDated = false
inputs.outOfDate { change ->
outDated = true
}
if(outDated) {
project.exec {
executable "make"
args hasProperty("extraArgs") ? extraArgs : "-f Makefile"
}
}
}
}
This most probably has something to do with inputs to tasks or messed up
condiguration/runtime stages of the tasks however I tried many options and
none seem to work.
So in the end I would like to have:
* `./configure`, `autotools` or `make` are not run unless their arguments change (`extraArgs` or `env`)
* when the arguments change, I'd like them all to run in a chain as specified by dependencies
* I would like `libxml2` to act like a project that can be linked with others and be able to match platform/architecture of the dependant, with linkage api, shared or static
Answer: So it seems its better to just call the build system that is shipped with the
library itself.
Here is the script that does it:
task autoReconfigure(type : Exec) {
executable "autoreconf"
args "-vif"
workingDir "."
}
task configureTask(type : Exec, dependsOn : autoReconfigure) {
executable "./configure"
args "--without-zlib"
workingDir "."
}
task makeFileTask(type : Exec, dependsOn : configureTask) {
executable "make"
args "-f", "Makefile"
workingDir "."
}
build.dependsOn(makeFileTask)
assemble.dependsOn(makeFileTask)
I will try to add support for different toolchains/platforms as I go along
|
making multi-index in pandas dataframes in Python?
Question: I have a data set where there is a matrix of numeric values indexed by a time
variable. Each matrix is a numpy array (that can be converted into a dataframe
with columns corresponding to columns of the matrix). if i have these matrices
how can i make them into a single dataframe where each matrix has a time
index? specifically:
# time t1
d1 = pandas.DataFrame({"a": [1,2,3,4], "b":[10,20,30,40]})
# time t2
d2 = pandas.DataFrame({"a": [10,20,30,40], "b": [1,2,5,6]})
# time t3
d3 = ...
i want to make an index called "time" to index these dataframes, and then
aggregate values from columns "a" and "b" across the time index. how can you
do this in pandas?
my attempt:
d=pandas.DataFrame([d1,d2],index=(0, 1),columns=["time"])
_update_ : unutbu's solution for adding two hierarchical columns is:
` c = pd.concat([d1, d2], keys=[('t1', 'p1'), ('t2', 'p2')], names=['time',
'position']) `
my final question is how do you access this resulting structure? for example
how do you do vectorized operations across `time`, or across `position`? eg
take the average of the rows for each value of `time`.
also, how does this compare to encoding `time` and `position` into each
dataframe and using `groupby`? in other words when to use levels versus flat
columns that are grouped? here's an alternative solution using flat dataframe
with groupby:
d1["time"] = 1
d1["position"] = "x"
d2["time"] = 2
d2["position"] = "y"
c = pandas.concat([d1, d2])
# take mean for all time values
c.groupby("time").apply(lambda x: np.mean(x, axis=1))
Answer: Given
import pandas as pd
d1 = pd.DataFrame({"a": [1,2,3,4], "b":[10,20,30,40]})
d2 = pd.DataFrame({"a": [10,20,30,40], "b": [1,2,5,6]})
then [`pd.concat([d1, d2], keys=['t1',
't2'])`](http://pandas.pydata.org/pandas-
docs/stable/generated/pandas.concat.html) returns:
In [177]: pd.concat([d1, d2], keys=['t1', 't2'])
Out[177]:
a b
t1 0 1 10
1 2 20
2 3 30
3 4 40
t2 0 10 1
1 20 2
2 30 5
3 40 6
* * *
If you wish to add more than one level to the new MultiIndex, you can instead
pass a _list of tuples_ to the `keys` parameter:
In [237]: pd.concat([d1, d2], keys=[('t1', 'p1'), ('t2', 'p2')], names=['time', 'position'])
Out[237]:
a b
time position
t1 p1 0 1 10
1 2 20
2 3 30
3 4 40
t2 p2 0 10 1
1 20 2
2 30 5
3 40 6
Note, it is important here that `keys` receives a list of **tuples** , rather
than a list of lists.
|
Animating quiver in matplotlib
Question: I followed some suggested code in response to this question, [Plotting
animated quivers in
Python](http://stackoverflow.com/questions/19329039/plotting-animated-quivers-
in-python), but I'm finding I have a problem that one did not address.
consider the following code:
from matplotlib import pyplot as plt
import numpy as np
import matplotlib.animation as animation
def ufield(x,y,t):
return np.cos(x+y)*np.sin(t)
def vfield(x,y,t):
return np.sin(x+y)*np.cos(t)
x = np.linspace(0,10, num=11)
y = np.linspace(0,10, num=11)
X,Y = np.meshgrid(x,y)
t = np.linspace(0,1)
def update_quiver(j, ax, fig):
u = ufield(X,Y,t[j])
v = vfield(X,Y,t[j])
Q.set_UVC(u, v)
ax.set_title('$t$ = '+ str(t[j]))
return Q,
fig =plt.figure()
ax = fig.gca()
u = ufield(X,Y,t[0])
v = vfield(X,Y,t[0])
Q = ax.quiver(X, Y, u, v)
ax.set_title('$t$ = '+ str(t[0]))
ax.set_xlabel('$x$')
ax.set_ylabel('$y$')
ani = animation.FuncAnimation(fig, update_quiver,
frames = range(0,t.size),
interval=1,fargs=(ax, fig))
plt.show()
This code runs fine, without a problem. But, if I want to use an init_func,
and I do, because I want to do more with my animation, I tried:
def init_quiver():
u = ufield(X,Y,t[0])
v = vfield(X,Y,t[0])
Q = ax.quiver(X, Y, u, v)
ax.set_title('$t$ = '+ str(t[0]))
ax.set_xlabel('$x$')
ax.set_ylabel('$y$')
return Q,
remove these lines from the main body of the script
u = ufield(X,Y,t[0])
v = vfield(X,Y,t[0])
Q = ax.quiver(X, Y, u, v)
and update the animation lines as follows:
ani = animation.FuncAnimation(fig, update_quiver,
frames = range(0,t.size),
init_func=init_quiver,
interval=1,fargs=(ax, fig))
plt.show()
But when I run this, I see the first frame, and nothing ever updates.
Answer: When I run your script, I see the behaviour you describe, and in the terminal
where I run it, I get an error with a Traceback ending:
>
> File "quiv.py", line 21, in update_quiver
> Q.set_UVC(u, v)
> NameError: global name 'Q' is not defined
>
You can rectify this by adding the line
global Q
as the first line of your `init_quiver` function.
The complete code now reads:
from matplotlib import pyplot as plt
import numpy as np
import matplotlib.animation as animation
def ufield(x,y,t):
return np.cos(x+y)*np.sin(t)
def vfield(x,y,t):
return np.sin(x+y)*np.cos(t)
x = np.linspace(0,10, num=11)
y = np.linspace(0,10, num=11)
X,Y = np.meshgrid(x,y)
t = np.linspace(0,1)
def update_quiver(j, ax, fig):
u = ufield(X,Y,t[j])
v = vfield(X,Y,t[j])
Q.set_UVC(u, v)
ax.set_title('$t$ = '+ str(t[j]))
return Q,
def init_quiver():
global Q
u = ufield(X,Y,t[0])
v = vfield(X,Y,t[0])
Q = ax.quiver(X, Y, u, v)
ax.set_title('$t$ = '+ str(t[0]))
ax.set_xlabel('$x$')
ax.set_ylabel('$y$')
return Q,
fig =plt.figure()
ax = fig.gca()
ax.set_title('$t$ = '+ str(t[0]))
ax.set_xlabel('$x$')
ax.set_ylabel('$y$')
ani = animation.FuncAnimation(fig, update_quiver,
frames = range(0,t.size),
init_func=init_quiver,
interval=1,fargs=(ax, fig))
plt.show()
|
Python: difficulty converting ascii to unicode
Question: My goal: get the page source from a url and count all instances of a keyword
within that page source
How I am doing it: getting the pagesource via urllib2, looping through each
char of the page source and comparing it to the keyword
My problem: my keyword is encoded in utf-8 while the page source is in
ascii... I am running into errors whenever I try conversions.
getting the page source:
import urllib2
response = urllib2.urlopen(myUrl)
return response.read()
comparing page source and keyword:
pageSource[i] == keyWord[j]
I need to convert one of these strings to the other's encoding. Intuitively I
felt that ascii (the page source) to utf-8 (the key word) would be the best
and easiest, so:
pageSource = unicode(pageSource)
UnicodeDecodeError: 'ascii' codec can't decode byte __ in position __: ordinal not in range(128)
Answer: When trying to work with text, don't leave your data as byte strings. Decode
to Unicode early, encode back to bytes as late as possible.
Decode your downloaded network data:
import urllib2
response = urllib2.urlopen(myUrl)
# Latin-1 is the default for HTTP text/ responses, adjust as needed
codec = response.info().getparam('charset', 'latin1')
return response.read().decode(codec)
and do the same for your `keyWord` data. If it is encoded as UTF-8, decode it
as such, or use Unicode string literals.
You may want to read up on Python and Unicode:
* [The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)](http://joelonsoftware.com/articles/Unicode.html) by Joel Spolsky
* [Pragmatic Unicode](http://nedbatchelder.com/text/unipain.html) by Ned Batchelder
* The [Python Unicode HOWTO](http://docs.python.org/2/howto/unicode.html)
|
Web Scraper for dynamic forms in python
Question: I am trying to fill the form of this website
<http://www.marutisuzuki.com/Maruti-Price.aspx>.
It consists of three drop down lists. One is Model of the car, Second is the
state and third is city. The first two are static and the third, city is
generated dynamically depending upon the value of state, there is an onclick
java script event running which gets the values of corresponding cities in a
state.
I am familiar with mechanize module in python. I came across several links
telling me that I cannot handle **dynamic content** in mechanize. But this
link <http://toddhayton.com/2014/12/08/form-handling-with-mechanize-and-
beautifulsoup/> in the section "**Adding item dynamically** " states that I
can use mechanize to handle dynamic content but I did not understand this line
of code in it
`item = Item(br.form.find_control(name='searchAuxCountryID'),{'contents': '3',
'value': '3', 'label': 3})`
What is "Item" in this line of code corresponding to the city field in the
form. I came across selenium module which might help me handling dynamic drop
down list. But I was not able to find anything in its documentation or any
good blog on how to use it.
Can some one suggest me how to submit this form for different models, states
and cities? Any links on how to solve this problem will be appreciated. A
sample code in python on how to submit the form will be helpful. Thanks in
advance.
Answer: If you look at the request being sent to that site in developer tools, you'll
see that a POST is sent as soon as you select a state. The response that is
sent back has the form with the values in the city dropdown populated.
So, to replicate this in your script you want something like the following:
* Open the page
* Select the form
* Select values for model and state
* Submit the form
* Select the form from the response sent back
* Select value for city (it should be populated now)
* Submit the form
* Parse the response for the table of results
That will look something like:
#!/usr/bin/env python
import re
import mechanize
from bs4 import BeautifulSoup
def select_form(form):
return form.attrs.get('id', None) == 'form1'
def get_state_items(browser):
browser.select_form(predicate=select_form)
ctl = browser.form.find_control('ctl00$ContentPlaceHolder1$ddlState')
state_items = ctl.get_items()
return state_items[1:]
def get_city_items(browser):
browser.select_form(predicate=select_form)
ctl = browser.form.find_control('ctl00$ContentPlaceHolder1$ddlCity')
city_items = ctl.get_items()
return city_items[1:]
br = mechanize.Browser()
br.open('http://www.marutisuzuki.com/Maruti-Price.aspx')
br.select_form(predicate=select_form)
br.form['ctl00$ContentPlaceHolder1$ddlmodel'] = ['AK'] # model = Maruti Suzuki Alto K10
for state in get_state_items(br):
# 1 - Submit form for state.name to get cities for this state
br.select_form(predicate=select_form)
br.form['ctl00$ContentPlaceHolder1$ddlState'] = [ state.name ]
br.submit()
# 2 - Now the city dropdown is filled for state.name
for city in get_city_items(br):
br.select_form(predicate=select_form)
br.form['ctl00$ContentPlaceHolder1$ddlCity'] = [ city.name ]
br.submit()
s = BeautifulSoup(br.response().read())
t = s.find('table', id='ContentPlaceHolder1_dtDealer')
r = re.compile(r'^ContentPlaceHolder1_dtDealer_lblName_\d+$')
header_printed = False
for p in t.findAll('span', id=r):
tr = p.findParent('tr')
td = tr.findAll('td')
if header_printed is False:
str = '%s, %s' % (city.attrs['label'], state.attrs['label'])
print str
print '-' * len(str)
header_printed = True
print ' '.join(['%s' % x.text.strip() for x in td])
|
Changing tick labels without affecting the plot
Question: I am plotting a 2-D array in python using matplotlib and am having trouble
formatting the tick marks. So first, my data is currently organized as a 2-D
array with (elevation, latitude). I am plotting values of electron density as
a function of height and latitude (basically a longitudinal slice at a
specific time).
I want to label the x axis going from -90 to 90 degrees in 30 degree intervals
and the y values with another array of elevations (each model run has
different elevation values so I can't manually assign an arbitrary elevation).
I have arrays with latitude values in it and another with elevation values
both 1-D arrays.
Here is my code:
from netCDF4 import Dataset
import numpy as np
import matplotlib.pyplot as plt
#load the netcdf file into a variable
mar120="C:/Users/WillEvo/Desktop/sec_giptie_cpl_mar_120.nc"
#grab the data into a new variable
fh=Dataset(mar120,mode="r")
#assign model variable contents to python variables
lons=fh.variables['lon'][:]
lats=fh.variables['lat'][:]
var1=fh.variables['UN'][:]
#specifying which time and elevation to map
ionst=var1[0,:,:,21]
ionst=ionst[0:len(ionst)-1]
#close the netCDF file
fh.close()
#Set the figure, size, and resolution
plt.figure(figsize=(8,6), dpi=100, facecolor='white')
plt.subplot(1,1,1)
plt.imshow(ionst, origin='lower', interpolation='spline16')
plt.xticks([-90, -60, -30, 0, 30, 60, 90])
plt.show()
If I don't include the plt.xticks argument I get the following good image but
bad tick labels:
If I include the plt.xticks argument I get the following:
How can I fix this? I want the data to follow the change in axis (but be
accurate). I also need to do this for the y axis but without manually entering
values and instead feeding an array of values. Thanks
Answer: Use the `extent` argument of `imshow` to set the x and y ranges of the image,
and use `aspect='auto'` to allow the aspect ratio of the image to be adjusted
to fit the figure. For example, the following code
In [68]: from scipy.ndimage.filters import gaussian_filter
In [69]: np.random.seed(12345)
In [70]: a = np.random.randn(27, 36)
In [71]: b = gaussian_filter(a, 4)
In [72]: ymin = 0
In [73]: ymax = 1
In [74]: plt.imshow(b, origin='lower', extent=[-90, 90, ymin, ymax], aspect='auto')
Out[74]: <matplotlib.image.AxesImage at 0x1115f02d0>
In [75]: plt.xticks([-90, -60, -30, 0, 30, 60, 90])
Out[75]:
([<matplotlib.axis.XTick at 0x108307cd0>,
<matplotlib.axis.XTick at 0x1101c1c50>,
<matplotlib.axis.XTick at 0x1115d4610>,
<matplotlib.axis.XTick at 0x1115f0d90>,
<matplotlib.axis.XTick at 0x1115ff510>,
<matplotlib.axis.XTick at 0x11161db10>,
<matplotlib.axis.XTick at 0x111623090>],
<a list of 7 Text xticklabel objects>)
generates this plot:
|
How do I start an SSH session locally using Python?
Question: What I mean to ask is, if I am on System "A" (Linux) and I want to ssh into
System "B" (Windows): On System "A", I can do ssh [email protected] which will
prompt me to a password and when that gets authenticated, I will get to the
"$" of System "B" (on System "A").
1. how do I send username and password together as a single line (since I want to use a script)
2. How to achieve the scenario that I have above.
Answer: I generally do it with Paramiko, its easier
import paramiko
# ssh
print 'enter ssh'
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) # this will automatically add the keys
ssh.connect(machineHostName, username=user, password=password)
# Run your commands
# example 1 : ls command
print 'do a ls command'
stdin, stdout, stderr = ssh.exec_command('ls')
print stdout.readlines()
time.sleep(2)
# example 2 : change ip address
print 'changing ip address'
stdin, stdout, stderr = ssh.exec_command('sed -i -- s/'+oldIp+'/'+newIp+'/g /etc/sysconfig/network-scripts/ifcfg-eth0')
print stdout.readlines()
time.sleep(2)
To install Paramiko, you can download the tar.gz file from
[here](https://pypi.python.org/pypi/paramiko/1.15.2).
Assuming you are really new to python, how to install this :
* Download the `tar.gz` file
* Extract the contents to a folder
* `cd` into that extracted folder, from your terminal
* execute this `python setup.py install`
* then you can try something like the above example
NOTE : if you get stuck with installation comment here, and I can help you.
|
What happens in python when you use the thread function in this code
Question: My question is how does python create the thread for the testing of multiple
passwords? And why is it more efficient?
import zipfile
from threading import Thread
def extractFile(zFile, password):
try:
zFile.extractall(pwd=password)
print '[+] Found password ' + password + '\n'
except:
pass
def main():
zFile = zipfile.ZipFile('evil.zip')
passFile = open('dictionary.txt')
for line in passFile.readlines():
password = line.strip('\n')
t = Thread(target=extractFile, args=(zFile, password))
t.start()
if __name__ == '__main__':
main()`
Answer: The use of multi-threading makes this code less efficient.
The work that is being down here is CPU oriented. Python threads do not work
well at distributing CPU oriented work because only one thread can do work at
a time (because of the Python GIL or Global Intepreter Lock)!
Python threads are more useful for blocking operations such as network calls,
disk reads etc.
On top of this, making a lot of threads adds a great deal of overhead, because
there is a thread scheduler constantly switching which thread is running so
that no thread starves. In your example, there is a thread being _created for
each file in the line_ , which is pretty bad if there is more than 30-50
lines.
To answer your question:
> how does python create the thread for the testing of multiple passwords?
It simply runs the function `extractFile` in a new thread for each line in
your file.
> and why is it more efficient?
Due to limitations of the Python GIL, and overhead of having more than 20
threads, this is definitely **not** more efficient than running through the
entire file without multi-threading.
|
Use the same SSH object to issue "exec_command()" multiple times in Paramiko
Question: I want to use the same SSH object to issue `exec_command()` multiple times in
Paramiko module in Python.
The objective is to get output from the same session.
Is there a way to do it? The `exec_command()` closes channel once it completes
executing a command and thereafter a new ssh object is needed to execute a
following command .. but the sessions will differ which I do not want.
**Code**
import os, sys,
import connectlibs as ssh
s = ssh.connect("xxx.xx.xx.xxx", "Admin", "Admin")
channel = s.invoke_shell()
channel.send("net use F: \\\\xyz.xy.xc.xa\\dir\n")
>>>32
channel.send("net use")
>>>7
channel.recv(500)
'Last login: Tue Jun 2 23:52:29 2015 from xxx.xx.xx.xx\r\r\n\x1b]0;~\x07\r\r\n\x1b[32mAdmin@WIN \x1b[33m~\x1b[0m\r\r\n$ net use F: \\\\xyz.xy.xc.xa\\dir\r\nSystem error 67 has occurred.\r\r\n\r\r\nThe network name cannot be found.\r\r\n\r\r\n\x1b]0;~\x07\r\r\n\x1b[32mAdmin@WIN \x1b[33m~\x1b[0m\r\r\n$ net use'
>>>
Answer: An SSH session can have multiple channels indeed (but [Paramiko possibly does
not support it](http://stackoverflow.com/a/19867108/850848)).
But by a session you seem to imagine a "shell session". But that's not what
the SSH session is. A channel is actually what corresponds to a "shell
session".
In other words, even if you could open multiple "exec" channels with Paramiko
over the same SSH connection (session) and call `exec_command` on these, the
commands get executed in a _different shell session_. So it won't help you.
* * *
You can test this with PuTTY SSH client. The latest version (0.64) supports
[connection
sharing](http://the.earth.li/~sgtatham/putty/0.64/htmldoc/Chapter4.html#config-
ssh-sharing), what basically means that you can have more PuTTY windows (each
using its own channel) over a single SSH connection/session. If you execute a
command in one PuTTY window, and the commands changes an environment (line an
environment variable or a current working directory), the change won't get
reflected to the other PuTTY window, even if they share the same SSH
connection.
* * *
So you need to execute the commands in a one channel. Depending on your needs
(which are still not clear), you need to use "exec" or "shell" channel.
In either case you will have troubles determining where output of one command
ends and output of other command starts as they share the same "stream".
You can solve that by inserting an unique separator (string) in between and
search for it in the channel output stream.
channel = ssh.invoke_shell()
channel.send('ls\n')
channel.send('echo unique-string-separating-output-of-the-commands\n')
channel.send('pwd\n')
|
Reformatting dates in python
Question: I'm stuck with this python problem, I have a date in the format of month-day-
year and I need to change it to year-month-day format
Answer:
>>> import datetime
>>> datetime.datetime.strptime("06/03/2015", "%m/%d/%Y").strftime("%Y-%m-%d")
'2015-06-03'
* * *
This takes a date (June 3, 2015 in this case) as a string and parses it to a
datetime object using
[`strptime`](https://docs.python.org/2/library/datetime.html#datetime.datetime.strptime).
It then converts that to a string in the format you requested (YYYY-mm-dd)
using
[`strftime`](https://docs.python.org/2/library/datetime.html#datetime.datetime.strftime)
|
How do I run a Python Script in a Java web application?
Question: I need to run a Python script (write input and read output) inside my Java
application that will eventually be uploaded onto the web. How do I do this
such that it is compatible with the web? I've tried things like `Jython` and
`Runtime.exec()` in Java and I think both require `Python` to be installed on
the computer (correct me if I'm wrong) but I want the app to be run by anyone
on the web.
The Python script imports `win32com.client` to operate on a `COM` object. It
reads in a .csv file, runs the external software, then writes a .csv file
using the methods RCSV(...), Run(...) and WCSV(...). Instead of a .csv file, I
would like this data to be accessed from my Java app directly. This is my
python script in full for reference:
import win32com.client
from win32com.client import VARIANT
import csv
# This will import VT_VARIANT
import pythoncom
#dictionary function designed to read .csv file
def RCSV(address):
input=[]
csv_reader = csv.DictReader(open(address, 'r'), delimiter=',', quotechar='"')
headers = csv_reader.fieldnames
for line in csv_reader:
for i in range(len(csv_reader.fieldnames)):
input.append(line[csv_reader.fieldnames[i]])
InVal=[]
for i in range(int(len(input)/len(headers))):
InVal.append([])
for i in range(len(InVal)):
for j in range(i*len(headers), (i+1)*len(headers)):
InVal[i].append(input[j])
return InVal
#dictionary function which writes a .csv file given its address
def WCSV(address, output, headers):
with open(address, 'w') as csvfile:
writer = csv.DictWriter(csvfile, fieldnames=headers, lineterminator = '\n')
writer.writeheader()
for i in range(len(output[0])):
writer.writerow({headers[x]: output[x][i] for x in range(len(headers))})
def Run(InType,InDesc,InVal,OutType,OutDesc):
FieldArray = VARIANT(pythoncom.VT_VARIANT | pythoncom.VT_ARRAY, InDesc)
AllValueArray=[None]*len(InVal)
for i in range(len(InVal)):
AllValueArray[i]=VARIANT(pythoncom.VT_VARIANT | pythoncom.VT_ARRAY, InVal[i])
object.ChangeParametersMultipleElement(InType, FieldArray, AllValueArray)
object.RunScriptCommand("SolvePowerFlow")
OutVal = object.GetParametersMultipleElement(OutType, OutDesc,'')
return OutVal
# This will establish the connection
object = win32com.client.Dispatch("pwrworld.SimulatorAuto")
filename= r"C:\Users\janusz\Desktop\NTU microgrid topology\ICESO Scaledown microgrid.pwb"
object.OpenCase(filename)
# Reading inputs from a .csv
ADIN='IN.csv'
InVal = RCSV(ADIN)
InType = "GEN"
InDesc = ["BusNum", "GenID", "GenMW"]
OutType = "BUS"
OutDesc = ["BUSNUM", "BUSNAME", "BUSPUVOLT", "BUSANGLE", "BUSKVVOLT"]
OutVal = Run(InType,InDesc,InVal,OutType,OutDesc)
ADOUT='OUT.csv'
WCSV(ADOUT,OutVal[1],OutDesc)
#This will close the connection
del object
object = None
Answer: Jython works without Python being installed on the host, because it is a 100%
Java implementation of Python. That being said, only `win32` clients can run
win32 COM anything. So, that's never going to be compatible across any
platform but win32 (and possibly win64 through wow).
|
CSV, keep file open between each run/measurement
Question: I have a question regarding writing CSV-files. I have an instrument where I am
going to read a value each minute and write the value to a CSV file together
with a timestamp.
I have written a simple code which works, which is the first one below. But my
friend came up with a question: "Why are you opening and closing the file for
each run." I couldn't answer his question since I'm a newbie when it comes to
both programming and Python. Nevertheless, I tried to rewrite the code, so it
became like solution number 2 below and then asked my friend whether that was
better, but he couldn't answer me. So I hope you could help me out, what is
the difference between #1 and #2, both gives the same result when it comes to
reading the file afterwards.
Is it right that #1 will open and close the file for each run in the while
loop, and #2 will keep the file open and close it after the last run?
This is just a simple example, in reality, I am going to expand the code so it
will do a measurement every minute, run for 3-4 days and I am going to log
multiple voltages and up to 8 temperatures. So, in the end, the file can
become quite large and opening and closing the file can become a bit resource
consuming.
> Code #1:
import csv
import datetime
import time
no_meas = 5 #number of measurements
cur_meas = 1 # current measurement number
while cur_meas <= no_meas:
cur_time = datetime.datetime.strftime(datetime.datetime.now(), '%H:%M:%S')
with open('test.csv', 'a', newline='') as fp:
a = csv.writer(fp, delimiter=',')
data = [[cur_time, 'test-text']]
a.writerows(data)
cur_meas += 1
time.sleep(60)
> Code #2
import csv
import datetime
import time
no_meas = 5 #number of measurements
cur_meas = 1 # current measurement number
with open('test.csv', 'a', newline='') as fp:
while cur_meas <= no_of_meas:
cur_time = datetime.datetime.strftime(datetime.datetime.now(), '%H:%M:%S')
a = csv.writer(fp, delimiter=csv_delimiter)
data = [[cur_time, 'test-text']]
a.writerows(data)
cur_meas += 1
time.sleep(60)
Answer: If the the frequency of your writes to the file is high you may want to avoid
the open/close overhead. Nevertheless, from what you describe it doesn't seem
like an issue (1 open/close per minute for writing a couple of dozens of
measurements). Even after a few days your file should not exceed the 1-3MB
size.
Since you're planning to let it run for a few days, you should handle a
scenario of failure without losing the gathered data. In the first case you
won't lose any data. In the second case, I'd recommend adding a flush after
each write to make sure the data is written to disk:
a.writerows(data)
fp.flush()
os.fsync(fp.fileno())
|
extracting text from multiple urls
Question: I'm very green when it comes to Python but I see how powerful it is. I'd like
to try a few things with it but I'm pretty much teaching myself so please,
feel free to explain things in their most basic terms. :/
I tried the goose extraction tool to pull some text from a URL and it work
pretty well. I was pretty simple...
from goose import Goose
url = 'http://example.com'
g = Goose()
article = g.extract(url=url)
article.cleaned_text
I'd like to replicate the process so I can extract text from hundreds of URLs.
Is there a way to set this up so I can enter a list of URLs, extract text, and
then (my guess) I could join them together for NLP or whatever else I want to
do? Thanks in advance...
Answer: Simply put all the urls in a text file like:
http://example1.com
http://example2.com
http://example3.com
Then, use this list to loop across like,
from goose import Goose
# Read list of hundreds of urls from a file
url_list = open("url_list.txt", "r").read().split("\n")
# loop for each url
for url in url_list:
g = Goose()
article = g.extract(url=url)
# process/store ...
article.cleaned_text
Later, as you have the text required for analysis, go ahead with storing and
then processing in a separate code blocks.
|
celery: daemonic processes are not allowed to have children
Question: In Python (2.7) I try to create processes (with multiprocessing) in a celery
task (celery 3.1.17) but it gives the error:
daemonic processes are not allowed to have children
Googling it, I found that most recent versions of billiard fix the "bug" but I
have the most recent version (3.3.0.20) and the error is still happening. I
also tried to implement [this
workaround](http://stackoverflow.com/questions/6974695/python-process-pool-
non-daemonic#) in my celery task but it gives the same error.
Does anybody know how to do it? Any help is appreciated, Patrick
EDIT: snippets of code
Task:
from __future__ import absolute_import
from celery import shared_task
from embedder.models import Embedder
@shared_task
def embedder_update_task(embedder_id):
embedder = Embedder.objects.get(pk=embedder_id)
embedder.test()
_Artificial_ test function ([from
here](http://stackoverflow.com/questions/6974695/python-process-pool-non-
daemonic#)):
def sleepawhile(t):
print("Sleeping %i seconds..." % t)
time.sleep(t)
return t
def work(num_procs):
print("Creating %i (daemon) workers and jobs in child." % num_procs)
pool = mp.Pool(num_procs)
result = pool.map(sleepawhile,
[randint(1, 5) for x in range(num_procs)])
# The following is not really needed, since the (daemon) workers of the
# child's pool are killed when the child is terminated, but it's good
# practice to cleanup after ourselves anyway.
pool.close()
pool.join()
return result
def test(self):
print("Creating 5 (non-daemon) workers and jobs in main process.")
pool = MyPool(5)
result = pool.map(work, [randint(1, 5) for x in range(5)])
pool.close()
pool.join()
print(result)
My _real_ function:
import mulitprocessing as mp
def test(self):
self.init()
for saveindex in range(self.start_index,self.start_index+self.nsaves):
self.create_storage(saveindex)
# process creation:
procs = [mp.Process(name="Process-"+str(i),target=getattr(self,self.training_method),args=(saveindex,)) for i in range(self.nproc)]
for p in procs: p.start()
for p in procs: p.join()
print "End of task"
The init function defines a multiprocessing array and an object that share the
same memory so that all my processes can update this same array at the same
time:
mp_arr = mp.Array(c.c_double, np.random.rand(1000000)) # example
self.V = numpy.frombuffer(mp_arr.get_obj()) #all the processes can update V
Error generated when task is called:
[2015-06-04 09:47:46,659: INFO/MainProcess] Received task: embedder.tasks.embedder_update_task[09f8abae-649a-4abc-8381-bdf258d33dda]
[2015-06-04 09:47:47,674: WARNING/Worker-5] Creating 5 (non-daemon) workers and jobs in main process.
[2015-06-04 09:47:47,789: ERROR/MainProcess] Task embedder.tasks.embedder_update_task[09f8abae-649a-4abc-8381-bdf258d33dda] raised unexpected: AssertionError('daemonic processes are not allowed to have children',)
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/celery/app/trace.py", line 240, in trace_task
R = retval = fun(*args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/celery/app/trace.py", line 438, in __protected_call__
return self.run(*args, **kwargs)
File "/home/patrick/django/entite-tracker-master/entitetracker/embedder/tasks.py", line 21, in embedder_update_task
embedder.test()
File "/home/patrick/django/entite-tracker-master/entitetracker/embedder/models.py", line 475, in test
pool = MyPool(5)
File "/usr/lib/python2.7/multiprocessing/pool.py", line 159, in __init__
self._repopulate_pool()
File "/usr/lib/python2.7/multiprocessing/pool.py", line 223, in _repopulate_pool
w.start()
File "/usr/lib/python2.7/multiprocessing/process.py", line 124, in start
'daemonic processes are not allowed to have children'
AssertionError: daemonic processes are not allowed to have children
Answer: `billiard` and `multiprocessing` are different libraries - `billiard` is the
Celery project's own fork of `multiprocessing`. You will need to import
`billiard` and use it instead of `multiprocessing`
However the better answer is probably that you should refactor your code so
that you spawn more Celery tasks instead of using two different ways of
distributing your work.
You can do this using Celery
[canvas](http://celery.readthedocs.org/en/latest/userguide/canvas.html)
from celery import group
@app.task
def sleepawhile(t):
print("Sleeping %i seconds..." % t)
time.sleep(t)
return t
def work(num_procs):
return group(sleepawhile.s(randint(1, 5)) for x in range(num_procs)])
def test(self):
my_group = group(work(randint(1, 5)) for x in range(5))
result = my_group.apply_async()
result.get()
I've attempted to make a working version of your code that uses canvas
primitives instead of multiprocessing. However since your example was quite
artificial it's not easy to come up with something that makes sense.
Update:
Here is a translation of your real code that uses Celery canvas:
`tasks.py`:
@shared_task
run_training_method(saveindex, embedder_id):
embedder = Embedder.objects.get(pk=embedder_id)
embedder.training_method(saveindex)
`models.py`:
from tasks import run_training_method
from celery import group
class Embedder(Model):
def embedder_update_task(self):
my_group = []
for saveindex in range(self.start_index, self.start_index + self.nsaves):
self.create_storage(saveindex)
group.extend([run_training_method.subtask((saveindex, self.id))
for i in range(self.nproc)])
result = group(my_group).apply_async()
|
Find XML element 'start' and 'end' using tinyxml2 (or other C++ XML library)
Question: I am trying to iterate through the elements of an XML document, and firing
events on 'start' elements and 'end' elements.
This is pretty straight-forward in using Python's lxml module, and there is
even another question on SO regarding this:
[Using Python's xml.etree to find element start and end character
offsets](http://stackoverflow.com/questions/8111556/using-pythons-xml-etree-
to-find-element-start-and-end-character-offsets)
#!/usr/bin/python
import re, sys
from lxml import etree
from StringIO import StringIO
dtd = etree.DTD (open (sys.argv [1], "r"))
xml = etree.XML (open (sys.argv [2], "r").read ())
result = dtd.validate (xml)
for error in dtd.error_log.filter_from_errors():
print(error.message)
print(error.line)
print(error.column)
if result == True :
for event, elem in etree.iterwalk (xml, events=('start', 'end')) :
if event == 'start' :
print 'starting element:', elem.tag
elif event == 'end' :
print 'ending element:', elem.tag
if elem is not xml :
print elem.tail
I would like to do essentially the same thing using the tinyxml2 C++ XML
library, but I have not had any luck with this so far [**specifically finding
closing tags**].
I prefer tinyxml2 as it is 'tiny', but I am open to other C++ XML libs if they
can achieve this end (more easily).
If there is a better way to fire events on 'end tags' I am open to that as
well.
Answer: [tinyXml2](http://www.grinninglizard.com/tinyxml2/) offers a very basic(and
very fast) implementation to parser and navigate inside a xml structure.
[RapidXML](http://rapidxml.sourceforge.net/) is likely faster but it has the
same basic behavior.
I suggest if it is enterily mandatory catching event (start and end) use
Xerces because SAXParser allows catching when the parser is inside an xml
element and when it exits from the element also. The great inconvenience, in
my humble opinion, is the compilation under MSVC, it is damned tedious because
you must compile the apache commons in C++, but under gcc environment I think
is trivial in comparission. GoodLuck!
|
Python smtlib raising error when trying to send e-mail
Question: I copied this code right from the smtplib docs over here
import smtplib
def prompt(prompt):
return input(prompt).strip()
fromaddr = prompt("From: ")
toaddrs = prompt("To: ").split()
print("Enter message, end with ^D (Unix) or ^Z (Windows):")
# Add the From: and To: headers at the start!
msg = ("From: %s\r\nTo: %s\r\n\r\n"
% (fromaddr, ", ".join(toaddrs)))
while True:
try:
line = input()
except EOFError:
break
if not line:
break
msg = msg + line
print("Message length is", len(msg))
server = smtplib.SMTP('192.168.2.4')
server.set_debuglevel(1)
server.sendmail(fromaddr, toaddrs, msg)
server.quit()
However this error is raised:
Traceback (most recent call last):
File "C:\Python34\geenemail.py", line 24, in <module>
server = smtplib.SMTP('192.168.2.4')
File "C:\Python34\lib\smtplib.py", line 242, in __init__
(code, msg) = self.connect(host, port)
File "C:\Python34\lib\smtplib.py", line 321, in connect
self.sock = self._get_socket(host, port, self.timeout)
File "C:\Python34\lib\smtplib.py", line 292, in _get_socket
self.source_address)
File "C:\Python34\lib\socket.py", line 509, in create_connection
raise err
File "C:\Python34\lib\socket.py", line 500, in create_connection
sock.connect(sa)
ConnectionRefusedError: [WinError 10061] Kan geen verbinding maken omdat de doelcomputer de verbinding actief heeft geweigerd
I looked for similar problems but couldn't find a lot, only found someone who
said the firewall might be the problem --> I turned Avast/firewall off, got a
bluescreen from some reason, restarted my PC, Avast/firewall was still off but
still it raised the same error.
I have also tried giving a port value but I still get the same error. What
might be the problem?
Answer: The most likely reason for this error is that there is no SMTP server running
on the computer you are trying to connect to.
server = smtplib.SMTP('192.168.2.4')
`'192.168.2.4'` should be the address of the SMTP server you are trying to use
to send the email.
|
Where is the history file for ipython
Question: I can not determine where the ipython is storing its history.
a. There is no ~/.pythonhistory:
12:49:00/dashboards $ll ~/.py*
ls: /Users/steve/.py*: No such file or directory
b. Nothing special in the python startup file:
12:49:07/dashboards $echo $PYTHONSTARTUP
/shared/.pythonstartup
12:49:43/dashboards $cat /shared/.pythonstartup
import rlcompleter
import readline
readline.parse_and_bind("tab: complete")
c. BUT: i do have plenty of history available in ipython when I start it up.
So where is that history being stored?
_UPDATE_ the answer from @Stefano led the correct way: here is the actual path
13:30:05/shared $ll ~/.ipython/profile_default/history.sqlite
-rw-r--r-- 1 steve staff 372736 Jun 3 12:48 /Users/steve/.ipython/profile_default/history.sqlite
Answer: IPython history is stored in a SQLite database located in the profile
directory. By default:
~/.ipython/profile_default/history.sqlite
Older versions (1.x) stored profile data in `~/.config/ipython`, at least on
platforms conforming to [XDG basedir
specs](http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html)
(i.e. most Linux distributions).
Anyway, you can locate the profile directory with:
$ ipython locate profile default
Notice that the history database is shared between IPython and IPython3, if
both are installed.
|
Parsing binary data into separate variables in Python?
Question: Say I open a file in Python that contains a series of binary data.
with open(sys.argv[1]) as data_file:
logData = data_file.read()
I basically want to create a loop saying:
for each_word in logData:
var1 = first 8 bytes
var2 = next 16 bytes
var3 = next 8 bytes
C code to generate my binary file:
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
FILE *file;
int buffer = 0x03000201;
int buffer2= 0x010203;
file = fopen("test.bin", "wb");
if (file != NULL)
{
fwrite(&buffer, sizeof(buffer), 1, file);
fwrite(&buffer2, sizeof(buffer2), 1, file);
fclose(file);
}
return 0;
}
and this basically continues until the loop is over, iterating through the
bytes of data. How is this possible?
Answer: Use the [`struct` module](http://docs.python.org/2/library/struct.html), it
will also allow you to interpret the binary data in many ways; you need to
define the types in a string format documented with that library:
struct.unpack('=HHf255s', bytes)
The above example expects native byte-order, two unsigned shorts, a float and
a string of 255 characters.
Your code example becomes:
for each_word in logData:
var1, var2, var3 = struct.unpack('8s16s8s', each_word)
In case you get an error `TypeError: 'str' does not support the buffer
interface`, that is because `bytes` are expected, but you passed a `str`, so
convert it to bytes and specify the encoding (in this example, UTF-8):
for each_word in logData:
var1, var2, var3 = struct.unpack('8s16s8s', bytes(each_word, 'utf-8'))
But maybe the case that your 8/16 byte strings are long integers? In that case
use the appropriate format for struct.
_EDIT_ : it turns out you wanted to read 8 **bits** (not bytes), then the next
16 bits, then the next 8 bits, so you can read it as one (unsigned?) byte, one
short, and another byte. The format string you should use is `'=bhb'` (or
`'=BHB'` for unsigned). Example:
import struct
with open('test.bin','rb') as f:
var1, var2, var3 = struct.unpack('=BHB', f.read(4))
print(var1, var2, var3)
|
Using python to visit a link and print data
Question: I'm writing a web scraper and trying to get back Drake lyrics. My scraper has
to visit one site (main metrolyrics site) and then visit each individual song
link, then print out the lyrics.
I'm having trouble visiting the second link. I've searched around on
BeautifulSoup and am pretty confused. I'm wondering if you can help.
# this is intended to print all of the drake song lyrics on metrolyrics
from pyquery import PyQuery as pq
from lxml import etree
import requests
from bs4 import BeautifulSoup
# this visits the website
response = requests.get('http://www.metrolyrics.com/drake-lyrics.html')
# this separates the different types of content
doc = pq(response.content)
# this finds the titles in the content
titles = doc('.title')
# this visits each title, then prints each verse
for title in titles:
# this visits each title
response_title = requests.get(title)
# this separates the content
doc2 = pq(response_title.content)
# this finds the song lyrics
verse = doc2('.verse')
# this prints the song lyrics
print verse.text
In response_title = requests.get(title), python isn't recognizing that title
is a link, which makes sense. How do I get the actual in there, though?
Appreciate your help.
Answer: Replace
response_title = requests.get(title)
with
response_title = requests.get(title.attrib['href'])
Full working script (with fixed note from the comment below)
#!/usr/bin/python
from pyquery import PyQuery as pq
from lxml import etree
import requests
from bs4 import BeautifulSoup
# this visits the website
response = requests.get('http://www.metrolyrics.com/drake-lyrics.html')
# this separates the different types of content
doc = pq(response.content)
# this finds the titles in the content
titles = doc('.title')
# this visits each title, then prints each verse
for title in titles:
# this visits each title
#response_title = requests.get(title)
response_title = requests.get(title.attrib['href'])
# this separates the content
doc2 = pq(response_title.content)
# this finds the song lyrics
verse = doc2('.verse')
# this prints the song lyrics
print verse.text()
|
How to loop through list of options inside if statement in python 2.7?
Question: I am extracting items from a subdirectory containing a mixture of files that
are audio files in different formats and with different suffixes e.g.
`_master` or `_128k`.
I have specified higher up in the code a list of permitted extensions (e.g.
`.mp3`) so that I extract only files of the right formats for processing.
I also have a list (suffixExcluded) containing filename suffixes (e.g.
`_syndication`) I explicitly want to exclude from further processing.
How do I best write the line that effectively does:
if fileExtension in filesAllowed and [LIST OF EXCLUDED SUFFIXES] not in fileName:
Is there a neat, compact and elegant (pythonic) way of iterating through my
list of exclusions within this `if` clause, or do I need to set up a
subsidiary loop to test each item?
Answer: You can filter as you go, passing a tuple of the extensions you want to keep
and filtering those with any to remove any files with matching extensions that
don't contain any substring from your list of excluded substrings.
exc = [LIST OF EXCLUDED SUFFIXES]
import os
for f in os.listdir("path"):
if f.endswith((".mp4",".mp3",".avi")) and not any(e in f for e in exc):
You only need a single pass over the directory content without any need to
build a list first.
If you want to replace the forbidden substrings and not just exclude you can
use re.sub:
import os
import re
r = re.compile(r"|".join([e for e in exc]))
for f in os.listdir("path"):
if f.endswith((".mp4",".mp3",".avi")):
f = r.sub("",f)
|
Explanation of HEX value representation and Endianess
Question: I was working on a script to basically output some sample data as a binary
blob. I'm a new intern in the software field and vaguely remember the idea of
endianness.
I realize that the most significant bits for big-endian starts at the top and
works down the memory block.
If I have 0x03000201 and the data is being parsed to output 0 1 2, how does
this happen and what is being done to make that work in terms of bits, bytes,
etc.
I am wondering, in the example posted below, how the numbers are extracted to
form 0 1 2 when printing out the data stored in the variables.
For example: I am creating a couple lines of the binary blob using this file:
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
FILE *file;
int buffer = 0x03000201;
int buffer2= 0x010203;
file = fopen("test.bin", "wb");
if (file != NULL)
{
fwrite(&buffer, sizeof(buffer), 1, file);
fwrite(&buffer2, sizeof(buffer2), 1, file);
fclose(file);
}
return 0;
}
I then created a Python script to parse this data:
# Info About Parse
import struct
with open('test.bin','rb') as f:
while True:
data = f.read(4)
if not data: break
var1, var2, var3 = struct.unpack('=BHB', data)
print(var1, var2, var3)
Answer: Big or little endianness defines how to interpret a sequence of bytes longer
than one byte and how to store those in memory. Wikipedia will help you with
that.
> I was really just looking to understand how 0x0300020 when read 2 bytes at a
> time and reprinted yields 0 1 2.
You don't read 2 bytes at a time, you read 4 bytes: `data = f.read(4)`
f.read(size) reads some quantity of data and returns it as a string.
You unpack data using =BHB - byte, 2 bytes, byte. Endianness comes into play
only when you unpack data, all other IO calls in your code deal with byte
sequences.
Experiment with [unpack() Byte Order, Size, and
Alignment](https://docs.python.org/2/library/struct.html) You may also look at
file data with a HEX editor of your choice.
And if, after your research, you have a concrete question, ask here.
|
getting an iterable output from a telnet client in python
Question: I am trying to write a script to perform validation checks on a network device
(router,switch). I am using telnet to send commands to the device. I store the
output of the command telnetobject.read_until(prompt) into a file and then run
some validation checks over the stored output by iterating over it one line at
a time. Is there a way to iterate over the output without storing it in a
file? the issue is the read_until option gives the output in one string and
the output of the device i am trying to test has an output in a tabular form
which does not have a consistent delimiter on each line.
This is an example: import telnetlib
tn=telnetlib.Telnet('ip address')
pwd='password'
uid='userid'
tn.read_until("login: ")
tn.write(uid + "\n")
tn.read_until("Password:")
tn.write(pwd +'\n')
tn.read_until(">",5)
tn.write('port statistics show' + '\n')
op1=tn.read_until("*>",5)
with open ('stattest-temp.txt','w') as stat:
stat.write(op1)
above code was to get a particular output and store it in a file below code is
to iterate over the output..problem is it is in a tabular form and starts with
multiple '_ _ _' characters and each line in the table has different number of
elements if you split it using a delimiter, hence it becomes difficult to
iterate over output from tn.read_until as it is all one giant string'
with open ('stattest-temp.txt','r') as f:
for line_no,line in enumerate(f):
if line_no>5:
if '+---------------------------------+----------------+-----------+-----------+------------+\r' in line:
break
else:
x=line[:-1].split("|")
#print x
x1=x[1].strip()
x2=x[2].strip()
x3=x[3].strip()
x4=x[4].strip()
x5=x[5].strip()
if x4 =="YES":
print x1,x4
print 'Traffic loss observed'
elif x4=="No":
print "session recovered"
I am looking for a way to do part 2 of the above code without having to write
the output to a file
Answer: I think if you split the output string on newline characters, this should
replicate the effect of saving to a file and the iterating through lines.
Basically set this before your `for` loop:
f = op1.split('\n')
for line_no,line in enumerate(f):
if line_no>5:
if '+---------------------------------+----------------+-----------+-----------+------------+\r' in line:
break
else:
x=line[:-1].split("|")
#print x
x1=x[1].strip()
x2=x[2].strip()
x3=x[3].strip()
x4=x[4].strip()
x5=x[5].strip()
if x4 =="YES":
print x1,x4
print 'Traffic loss observed'
elif x4=="No":
print "session recovered"
|
Python encoding error? UnicodeDecodeError: 'ascii' codec can't decode byte ordinal not in range(128)
Question: I have an AWS autoscale instance. On the AMI for that instance, I have a file
`myfile.py` that contains the following string:
X5ZŒ
In my AWS Cloudformation, LaunchConfiguration, I have UserData that executes
the following python instruction when the instance is spun up. It simply reads
`myfile.py` and attempts to replace all occurrences of the regexp "X\dZ" with
"XYZ":
myString = "XYZ".join(re.compile('X\d\Z').split(open("myfile.py", "r").read()))
That produces this error:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc5 in position 4: ordinal not in range(128)
Okay. I understand that the character `Œ` is causing trouble because it is
non-ASCII. But when I manually run the same statement from the python shell,
it works fine without throwing any exception.
How can I force the script that is run by AWS LaunchConfig's UserData to have
the same behavior as when I run it manually myself? What encoding should I set
and how should I set it?
Answer: Your file is encoded, that means it represents unicode in a defined way. You
use some literal strings (e.g. `XYZ`), which shall be used to in oprations
together with the file content. These literal strings are encoded just like
the file, in which this code is defined.
Python tries to coerce both into the same to be able to operate on it. It is
best, if you convert both into unicode. For the string literals, just prepend
a `u`, like so: `u"XYZ"`. For the file you have to tell python the encoding,
if you don't, it by default assumes `ascii`. Try:
myString = u"XYZ".join(re.compile(u'X\d\Z').split(
open("myfile.py", "r").read().decode('utf-8')))
in this version I used `utf-8`, which has some probability of being right. If
you know it being different, you'd have to substitute it for the [right
one](https://docs.python.org/2/library/codecs.html#standard-encodings) (your
editor in which you saved the file can probably tell you).
EDIT: I removed the part about console and environment settings, which don't
apply, as @Martijn mentioned. He's also right about, that this error is only
reproducible if your string literals _are_ already implicitly unicode (`from
__future__ import unicode_literals`) - in this case there's no need to prepend
the string literals with a `u`.
|
Python csv seek() not working
Question: Hi I am trying to read a csv file using the following code. I want to read
from `n` th line to `m` th line of the csv file provided. As a example I want
to start reading from 10th line to 100 line and after that start from 500th
line to 1000th line. I give those parameters using `start` and `end`
variables.
The problem that **it always start from the beginning regardless the start and
end variables.** i tried and tried for a solution but failed.Can anyone help
me to figure out the issue here.? Thanks a lot! (there are some duplicate
questions but no one seems to have given a solution)
import csv
import os
with open('file.csv','r') as csvfile:
start=10
end=100
csvfile.seek(start)
r= csv.reader(csvfile)
r.next()
for i in range(start,end):
try:
url=r.next()[2]
print url
except IndexError,e:
print str(e),
except ValueError,b:
print b
csvfile.close()
Answer: Use the [`csv`](https://docs.python.org/3.4/library/csv.html) module.
import csv
n = 3
m = 5
read = 0
with open("so.csv") as csvfile:
reader = csv.reader(csvfile)
for record in reader:
read += 1
if read >= n and read <= m:
print(record)
|
'module' csv has no attribute next
Question: I am using a csv iterator to go through a csv file, which contains data
associated with time. I am sure the csv file is correct. I am using Jupyter,
iPython notebook in python 3.x
When I try to iterate on the first row by using .next() method, I have an
AttributeError: 'module' object has no attribute 'next'.
My code is divided in two parts, one part containing function and imports, one
part calling them. The function I have a problem with is:
def get_durations(csvfile):
try:
csvfile = iter(csvfile)
except TypeError, te:
print csvfile, 'is not iterable'
print "data is", repr(csvfile)
first_time = csvfile.next()[5]
first_time = (first_time.replace(" ", ""));
for row in csvfile:
last_time = row[5]
last_time = (last_time.replace(" ", ""))
first_time = datetime.datetime.strptime(first_time, "%H:%M:%S")
last_time = datetime.datetime.strptime(last_time, "%H:%M:%S")
return first_time.replace(second = 0), last_time.replace(second = 0)
I make the call to the function here:
for el_mousefile in mousefiles:
os.chdir(el_mousefile)
print "data is", repr(csvfile)
csvfile = csv.reader(open("mouse.csv", "rU"), delimiter=';', quoting=csv.QUOTE_NONE)
print "data is", repr(csvfile)
try:
csvfile = iter(csvfile)
except TypeError, te:
print csvfile, 'is not iterable'
first_time, last_time = get_durations(csv)
I get this output when trying to run the program:
data is <_csv.reader object at 0x000000000A388D08>
data is <_csv.reader object at 0x000000000A388948>
module 'csv' from 'C:\Users\**\AppData\Local\Continuum\Anaconda\lib\csv.pyc' is not iterable
data is module 'csv' from 'C:\Users\**\AppData\Local\Continuum\Anaconda\lib\csv.pyc'
96------>first_time = csvfile.next()[5]
97 first_time = (first_time.replace(" ", ""));
98 for row in csvfile:
AttributeError: 'module' object has no attribute 'next'
I don't understand how can my csv be iterable in the second part, but then
when being passed to the function, it is not iterable anymore which is
responsible for my error.
Answer:
first_time, last_time = get_durations(csv)
You are passing in the csv module, not a file.
|
Can this Python code be further shrunk?
Question: Below is Python code that fetches all of the sub-domains within a domain. It
takes a file as input that contains the page source for a website. The second
argument is the domain name. For example: `"https://www.sometime.com"`.
import re
def getSubDomains(fil,domain):
with open(fil) as f:
subDomainLst = []
for line in f:
m = re.findall(r'\bhref="\https://[\w+\.*]+%s/'%domain,line)
if(m):
for ele in m: subDomainLst.append(ele.split('/')[2])
else:
continue
subDomainLst = list(set(subDomainLst))
for ele in subDomainLst: print ele
def main():
fil1,domain1 = raw_input("Enter the file name\n"),raw_input("Enter the domain\n")
getSubDomains(fil1,domain1)
main() if __name__ == '__main__' else Pass
I've tried shrinking the inner 'if else statement' to
for ele in m: subDomainLst.append(ele.split('/')[2]) if(m) else continue
But this gives an error.
Can the above code be shrunk further (16 lines for now) so that it takes up
minimum number of lines and become more pythonic?
Answer: You don't need to add _continue_. You can try doing like this, even though I
DO NOT recommend as it makes the code unreadable.
subDomainLst = [ele.split('/')[2] for line in f for ele in re.findall(r'\bhref="\https://[\w+\.*]+%s/' % domain, line)]
Btw you should indent your code by 4 spaces and try to avoid one-line
uncomprehensible statements: pythonic means also readable
Complete code:
if __name__ == '__main__':
import re
fil, domain = raw_input("Enter the file name\n"), raw_input("Enter the domain\n")
with open(fil) as f:
print '\n'.join([ele.split('/')[2] for line in f for ele in re.findall(r'\bhref="\https://[\w+\.*]+%s/' % domain, line)])
|
how to make feature vector from the lists
Question: I'm new to python. Actually I have a train data which is in bag of words.Each
line of the train data is an article. The labels of the train data is in
another file and each i label is equal to i article in the train data. I did
stemming on the train data and also removed the stop words. The output is the
lists of words of each article(line). Now I want to extract a feature vector
of it and then use it in my KNN classifier in python.. I don't know how to do
it! I appreciate any quick answer. Here's my code up to the things I did:
import nltk
from nltk.corpus import stopwords
from nltk import stem
stemmer=stem.PorterStemmer()
with open('data.txt')as file:
while 1:
line=file.readline().split()
filtered_words = [w for w in line if not w in stopwords.words('english')]
documents = [stemmer.stem(line) for line in filtered_words]
print(documents)
if not line:
break
pass
Answer: Take a look at Scikit-learn's [CountVectorizer](http://scikit-
learn.org/stable/modules/generated/sklearn.feature_extraction.text.CountVectorizer.html#sklearn.feature_extraction.text.CountVectorizer)
or [TfIdfVectorizer](http://scikit-
learn.org/stable/modules/generated/sklearn.feature_extraction.text.TfidfVectorizer.html#sklearn.feature_extraction.text.TfidfVectorizer).
These can take a list of documents (these are lists of tokens, as in your
example) as their input, and return a feature matrix:
from sklearn.feature_extraction.text import CountVectorizer
count_vect = CountVectorizer()
X_train_counts = count_vect.fit_transform(your_list_of_documents)
You can find more information in the [Working with Text Data
Tutorial](http://scikit-
learn.org/stable/tutorial/text_analytics/working_with_text_data.html).
|
Send email django from any host
Question: I have read plenty of links for sending emails through django. I've tried all
of them but they don't work. I tried sending an email through the python shell
and I get '1'. \- So what are the settings that I should use for the email to
work, I'm willing to use any mail server? \- I was using gmail but I read that
it causes problems, if I'm going to use hotmail for example do I need to
specify the email password in the settings.xml? \- how to debug this problem?
Answer: You can try yagmail, it should make it a lot easier:
import yagmail
yag = yagmail.Connect('[email protected]', 'password')
yagmail.send(email_to, subject = 'site down!', contents = 'with some error')
It has a lot more features, for example how to make it easier to send
attachments etc.
yagmail can be found at [github](https://github.com/kootenpv/yagmail).
You will probably have to install it first using pip:
pip install yagmail # python 2
pip3 install yagmail # python 3
|
Script doesn't autorizate in strava.com
Question: I want to login in strava.com with python. I try do it (using
<http://www.youtube.com/watch?v=eRSJSKG4mDA>), but i can't...
import requests
import bs4
with requests.Session() as c:
url='https://strava.com/login'
url_p='https://strava.com/session'
Email='[email protected]'
Password='12345678'
html = c.get(url,verify=True)
soup = bs4.BeautifulSoup(html.text)
loginForm = soup.find('form', {'id': 'login_form'})
hiddenAuthKey = soup.find('input', {'name': 'authenticity_token'})['value']
print hiddenAuthKey
login_data=dict(utf8="True",authenticity_token=hiddenAuthKey,plan='',email=Email,password=Password,remember_me='on')
c.post(url_p,data=login_data,headers={"Referer":"https://www.strava.com/"},verify=True)
page = c.get('https://www.strava.com/dashboard/new/web',verify=True)
f=codecs.open('st.html','wb')
f.write(page.content)
f.close()
Answer: It is much easier if, instead of using requests, you use
[`mechanize`](http://wwwsearch.sourceforge.net/mechanize/).
>>> import mechanize
>>> br = mechanize.Browser()
>>> response = br.open('https://strava.com/login')
>>> br.select_form(nr=0) # selects the first form on the login page
View the form's fields:
>>> print br.form
<POST https://www.strava.com/session application/x-www-form-urlencoded
<HiddenControl(utf8=✓) (readonly)>
<HiddenControl(authenticity_token=XgZFBcwDxCfax4AOGoDCjMYjVvM6X/iB6nSH/Cp1Um4=) (readonly)>
<HiddenControl(plan=) (readonly)>
<TextControl(email=)>
<PasswordControl(password=)>
<CheckboxControl(remember_me=[on])>
<SubmitButtonControl(<None>=) (readonly)>>
Set the required values for username and password:
>>> br.form['email'] = '[email protected]'
>>> br.form['password'] = 'xxxxxxxx'
>>> print br.form
<POST https://www.strava.com/session application/x-www-form-urlencoded
<HiddenControl(utf8=✓) (readonly)>
<HiddenControl(authenticity_token=XgZFBcwDxCfax4AOGoDCjMYjVvM6X/iB6nSH/Cp1Um4=) (readonly)>
<HiddenControl(plan=) (readonly)>
<TextControl([email protected])>
<PasswordControl(password=xxxxxxxx)>
<CheckboxControl(remember_me=[on])>
<SubmitButtonControl(<None>=) (readonly)>>
And submit the form:
>>> response = br.submit()
You should now be logged in...
>>> print br.geturl()
https://www.strava.com/dashboard/new/web
You can save the page to a file:
with open('st.html', 'w') as f:
f.write(response.read())
Note also that you have posted a working login and password, you might want to
change your password to prevent undesired logins.
|
Insert hyperlink to a local folder in Excel with Python
Question: The piece of code reads an Excel file. This excel file holds information such
as customer job numbers, customer names, sites, works description ect..
What this code will do when completed (I hope) is read the last line of the
worksheet (this is taken from a counter on the worksheet at cell 'P1'), create
folders based on cell content, and create a hyperlink on the worksheet to open
the lowest local folder that was created.
I have extracted the info I need from the worksheet to understand what folders
need to be created, but I am not able to write a hyperlink to the cell on the
row in column B.
#Insert Hyperlink to folder
def folder_hyperlink(last_row_position, destination):
cols = 'B'
rows = str(last_row_position)
position = cols + rows
final_position = "".join(position)
print final_position # This is just to check the value
# The statement below should insert hyperlink in eps.xlsm > worksheet jobnoeps at column B and last completed row.
ws.cell(final_position).hyperlink = destination
The complete code is below but here is the section that is meant to create the
hyperlink. I have also tried the 'xlswriter' package with no joy. Searched the
internet and the above snippet is the result of what I found.
Anyone know what I am doing wrong?
__author__ = 'Paul'
import os
import openpyxl
from openpyxl import load_workbook
import xlsxwriter
site_info_root = 'C:\\Users\\paul.EPSCONSTRUCTION\\PycharmProjects\\Excel_Jobs\\Site Information\\'
# This function returns the last row on eps.xlsm to be populated
def get_last_row(cell_ref = 'P1'): #P1 contains the count of the used rows
global wb
global ws
wb = load_workbook("eps.xlsm", data_only = True) #Workbook
ws = wb["jobnoeps"] #Worksheet
last_row = ws.cell(cell_ref).value #Value of P1 from that worksheet
return last_row
# This function will read the job number in format EPS-XXXX-YR
def read_last_row_jobno(last_row_position):
last_row_data = []
for cols in range(1, 5):
last_row_data += str(ws.cell(column = cols, row = last_row_position).value)
last_row_data_all = "".join(last_row_data)
return last_row_data_all
#This function will return the Customer
def read_last_row_cust(last_row_position):
cols = 5
customer_name = str(ws.cell(column = cols, row = last_row_position).value)
return customer_name
#This function will return the Site
def read_last_row_site(last_row_position):
cols = 6
site_name = str(ws.cell(column = cols, row = last_row_position).value)
return site_name
#This function will return the Job Discription
def read_last_row_disc(last_row_position):
cols = 7
site_disc = str(ws.cell(column = cols, row = last_row_position).value)
return site_disc
last_row = get_last_row()
job_no_details = read_last_row_jobno(last_row)
job_customer = read_last_row_cust(last_row)
job_site = read_last_row_site(last_row)
job_disc = read_last_row_disc(last_row)
cust_folder = job_customer
job_dir = job_no_details + "\\" + job_site + " - " + job_disc
#Insert Hyperlink to folder
def folder_hyperlink(last_row_position, destination):
cols = 'B'
rows = str(last_row_position)
position = cols + rows
final_position = "".join(position)
print final_position # This is just to check the value
# The statement below should insert hyperlink in eps.xlsm > worksheet jobnoeps at column B and last completed row.
ws.cell(final_position).hyperlink = destination
folder_location = site_info_root + job_customer + "\\" + job_dir
print folder_location # This is just to check the value
folder_hyperlink(last_row, folder_location)
* * *
Now my hyperlink function looks like this after trying xlsxwriter as advised.
##Insert Hyperlink to folder
def folder_hyperlink(last_row_position, destination):
import xlsxwriter
cols = 'B'
rows = str(last_row_position)
position = cols + rows
final_position = "".join(position)
print final_position # This is just to check the value
workbook = xlsxwriter.Workbook('eps.xlsx')
worksheet = workbook.add_worksheet('jobnoeps')
print worksheet
worksheet.write_url(final_position, 'folder_location')
workbook.close()
The function overwrites the exsisting eps.xlsx, creates a jobnoeps table and
then inserts the hyperlink. I have played with the following lines but don't
know how to get it to open the existing xlsx and existing jobnoeps tab and
then enter the hyperlink.
workbook = xlsxwriter.Workbook('eps.xlsx')
worksheet = workbook.add_worksheet('jobnoeps')
worksheet.write_url(final_position, 'folder_location')
Answer: The XlsxWriter
[`write_url()`](http://xlsxwriter.readthedocs.org/worksheet.html#worksheet-
write-url) method allows you to link to folders or other workbooks and
worksheets as well as internal links and links to web urls. For example:
import xlsxwriter
workbook = xlsxwriter.Workbook('links.xlsx')
worksheet = workbook.add_worksheet()
worksheet.set_column('A:A', 50)
# Link to a Folder.
worksheet.write_url('A1', r'external:C:\Temp')
# Link to a workbook.
worksheet.write_url('A3', r'external:C:\Temp\Book.xlsx')
# Link to a cell in a worksheet.
worksheet.write_url('A5', r'external:C:\Temp\Book.xlsx#Sheet1!C5')
workbook.close()
See the docs linked to above for more details.
|
Send the result of python cgi script to HTML
Question: I have a toggle button on a page 'index.html'. When I click on it, it executes
a python cgi script that changes the state of something on my raspberry.
To do so, I do this :
**HTML :**
<form id="tgleq" method="POST" action="/cgi-bin/remote.py" target="python_result">
<input id="toggle-eq" type="checkbox" data-toggle="toggle" name="toggle-eq" value="">
<script>
$(function() {
$('#toggle-eq').change(function() {
tgl_state = $('#toggle-eq').prop("checked")
var toggle = document.getElementById("toggle-eq");
toggle.value = tgl_state;
document.getElementById("tgleq").submit();
})
})
</script>
**CGI :**
#!/usr/bin/env python
import cgi
import cgitb
cgitb.enable()
print "Content-type: text/html\n\n"
print
form=cgi.FieldStorage()
arg1 = form.getvalue('toggle-eq')
And then I do what I want to do with my arg1.
Now, what I want is, when you open the web interface page, to get the state of
the raspberry component to initialize the toggle on the right position.
To do so I send a form on page load that launch a script looking at the state
of the component. But how can I get it back in the html ?
I tried [urllib](http://stackoverflow.com/questions/17509607/submitting-to-a-
web-form-using-python) and httplib2 but nothing worked for me... Any
suggestions ?
Thanks
Answer: If I understand your question correctly you want to show the current-state of
your switchable component on the webpage. Currently it looks like you have a
pure HTML page and an CGI page, so I think you have multiple options, one of
them is to combine the HTML and CGI into one page.
The code below is an example of this idea and probably doesn't work correctly,
so not a copy/paste solution.
#!/usr/bin/env python
import cgi
import cgitb
cgitb.enable()
print "Content-type: text/html\n\n"
print
active="""
<form id="tgleq" method="POST" action="/cgi-bin/remote.py" target="python_result">
<input id="toggle-eq" type="checkbox" data-toggle="toggle" name="toggle-eq" value="">
"""
inactive="""
<form id="tgleq" method="POST" action="/cgi-bin/remote.py" target="python_result">
<input id="toggle-eq" type="checkbox" data-toggle="toggle" name="toggle-eq" value="checked">
"""
generic = """
<script>
$(function() {
$('#toggle-eq').change(function() {
tgl_state = $('#toggle-eq').prop("checked")
var toggle = document.getElementById("toggle-eq");
toggle.value = tgl_state;
document.getElementById("tgleq").submit();
})
})
</script>
"""
def set_state(option):
if (option==True):
actual_state_Setting_here = 1 # <-magic happens here
else:
actual_state_Setting_here = 0 # <-magic happens here
def get_state():
return actual_state_Setting_here # <- read actual value here
form = cgi.FieldStorage()
if ( form.getvalue('toggle-eq')=="checked" ):
set_state(True)
else:
set_state(False)
if ( get_state()==True ):
print(active) #show as currently active
else:
print(inactive) #show as currently inactive
print(generic) #show rest of the page
|
"from math import sqrt" works but "import math" does not work. What is the reason?
Question: I am pretty new in programming, just learning python.
I'm using Komodo Edit 9.0 to write codes. So, when I write "from math import
sqrt", I can use the "sqrt" function without any problem. But if I only write
"import math", then "sqrt" function of that module doesn't work. What is the
reason behind this? Can I fix it somehow?
Answer: You have two options:
import math
math.sqrt()
will import the `math` module into its own namespace. This means that function
names have to be prefixed with `math`. This is good practice because it avoids
conflicts and won't overwrite a function that was already imported into the
current namespace.
Alternatively:
from math import *
sqrt()
will import everything from the `math` module into the current namespace.
[That can be problematic](http://stackoverflow.com/a/2360808/2202669).
|
Finding roots with scipy.optimize.root
Question: I am trying to find the root y of a function called f using Python.
Here is my code:
def f(y):
w,p1,p2,p3,p4,p5,p6,p7 = y[:8]
t1 = w - 0.500371726*(p1**0.92894164) - (-0.998515304)*((1-p1)**1.1376649)
t2 = w - 8.095873128*(p2**0.92894164) - (-0.998515304)*((1-p2)**1.1376649)
t3 = w - 220.2054377*(p3**0.92894164) - (-0.998515304)*((1-p3)**1.1376649)
t4 = w - 12.52760758*(p4**0.92894164) - (-0.998515304)*((1-p4)**1.1376649)
t5 = w - 8.710859537*(p5**0.92894164) - (-0.998515304)*((1-p5)**1.1376649)
t6 = w - 36.66350261*(p6**0.92894164) - (-0.998515304)*((1-p6)**1.1376649)
t7 = w - 3.922692207*(p7**0.92894164) - (-0.998515304)*((1-p7)**1.1376649)
t8 = p1 + p2 + p3 + p4 + p5 + p6 + p7 - 1
return [t1,t2,t3,t4,t5,t6,t7,t8]
x0 = np.array([-0.01,0.3,0.1,0.2,0.1,0.1,0.1,0.1])
sol = scipy.optimize.root(f, x0, method='lm')
print sol
print 'solution', sol.x
print 'success', sol.success
Python does not find the root whatever the method I try in
scipy.optimize.root.
However there is one, I found it with the function fsolve in Matlab.
It is:
[-0.0622, 0.5855, 0.087, 0.0028, 0.0568, 0.0811, 0.0188, 0.1679].
When I specify x0 close to the root, the python algorithm converges. The
problem is that I have no idea a priori on the root to specify x0. In reality
I am solving many equations of this type.
I really want to use Python. Can anyone help me converge with python?
Answer: OK, after some fooling around, we focus on another aspect of good
optimization/root finding algorithms. In the comments above we went back and
forth around which method in scipy.optimize.root() to use. An equally
important question for near-bulletproof 'automatic' root finding is zeroing in
on good initial guesses. Often times, good initial guesses are, in fact, not
near the real answer at all. Instead, they need to be arranged so that they
will naturally lead the solver in the right direction.
In your particular case, your guesses were, in fact, sending the algorithm off
in strange directions.
My toy reconstruction of your problem is:
import numpy as np
import scipy as sp
import scipy.optimize
def f(y):
w,p1,p2,p3,p4,p5,p6,p7 = y[:8]
def t(p,w,a):
b = -0.998515304
e1 = 0.92894164
e2 = 1.1376649
return(w-a*p**e1 - b*(1-p)**e2)
t1 = t(p1,w,1.0)
t2 = t(p2,w,4.0)
t3 = t(p3,w,16.0)
t4 = t(p4,w,64.0)
t5 = t(p5,w,256.0)
t6 = t(p6,w,512.0)
t7 = t(p7,w,1024.0)
t8 = p1 + p2 + p3 + p4 + p5 + p6 + p7 - 1.0
return(t1,t2,t3,t4,t5,t6,t7,t8)
guess = 0.0001
x0 = np.array([-1000.0,guess,guess,guess,guess,guess,guess,guess])
sol = sp.optimize.root(f, x0, method='lm')
print('w=-1000: ', sol.x, sol.success,sol.nfev,np.sum(f(sol.x)))
Note that I did not use your specific prefactors (I wanted to broaden the
range I explored), although I kept your particular exponents on the p terms.
The real secret is in the initial guess, which I made the same for all p
terms. Having it a 0.1 or above bombed much of the time, since some terms want
to go one way and some the other. Reducing it to 0.01 worked well for this
problem. (I will note that the w term is very robust - varying from -1000. to
+1000. had no effect on the solution). Reducing the initial guess even further
has no effect on this particular problem, but it does no harm either. I would
keep it very small.
Yes, you know that at least some terms will be much larger. But, you are
putting the solver in a position where it can clearly and directly proceed
towards the real solution.
Good luck.
|
How to detect the terminal that is running python?
Question: I've already tried sys.platform, platform.system() and os.name but none of
them return something related to cygwin (I always get win32, Windows and nt as
output). Maybe because my python was installed on windows (8.1) and not
through cygwin. I need to detect if my python file is being executed by cygwin
or cmd.
Answer: Cygwin uses Linux-style paths; thus you might be able to check the path
separator:
import sys
import os.path
def running_cygwin():
return sys.platform == 'win32' and os.path.sep == '/'
(I don't have a Cygwin here, so this is untested.)
|
Python urllib2 request error
Question:
Python 2.7.3 (default, Mar 13 2014, 11:03:55)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import urllib2
>>> req = urllib2.Request("http:///wp-login.php")
>>> website='kseek.com.my'
>>> req = urllib2.Request("http://"+website+"/wp-login.php")
>>> req.add_header('User-agent', 'Mozilla 5.10')
>>> req.add_header('Referer', 'http://'+website)
>>> data = urllib2.urlopen(req, timeout=6).read()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/urllib2.py", line 127, in urlopen
return _opener.open(url, data, timeout)
File "/usr/lib/python2.7/urllib2.py", line 407, in open
response = meth(req, response)
File "/usr/lib/python2.7/urllib2.py", line 520, in http_response
'http', request, response, code, msg, hdrs)
File "/usr/lib/python2.7/urllib2.py", line 445, in error
return self._call_chain(*args)
File "/usr/lib/python2.7/urllib2.py", line 379, in _call_chain
result = func(*args)
File "/usr/lib/python2.7/urllib2.py", line 528, in http_error_default
raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
urllib2.HTTPError: HTTP Error 406: Not Acceptable
>>> req = urllib2.Request("http://"+website+"/")
>>> req.add_header('User-agent', 'Mozilla 5.10')
>>> req.add_header('Referer', 'http://'+website)
>>> data = urllib2.urlopen(req, timeout=6).read()
>>>
As you notice, When requesting /wp-login.php which i can reach manually via
browser ow even curl I get 406 error while with the same method requesting
/index.php , work without problem Any help?
Answer: You're getting [HTTP error 406](http://www.checkupdown.com/status/E406.html)
because you're missing the `Accept` header. Add the following before you open
the URL:
req.add_header('Accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8')
**OUTPUT:**
>>> req.add_header('Accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8')
>>> data = urllib2.urlopen(req, timeout=6).read()
>>> print data
<!DOCTYPE html>
<!--[if IE 8]>
<html xmlns="http://www.w3.org/1999/xhtml" class="ie8" lang="en-US">
<![endif]-->
<!--[if !(IE 8) ]><!-->
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US">
<!--<![endif]-->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>K SEE K architect › Log In</title>
<link rel='stylesheet' id='buttons-css' href='http://kseek.com.my/wp-includes/css/buttons.min.css?ver=4.2.2' type='text/css' media='all' />
<link rel='stylesheet' id='open-sans-css' href='//fonts.googleapis.com/css?family=Open+Sans%3A300italic%2C400italic%2C600italic%2C300%2C400%2C600&subset=latin%2Clatin-ext&ver=4.2.2' type='text/css' media='all' />
<link rel='stylesheet' id='dashicons-css' href='http://kseek.com.my/wp-includes/css/dashicons.min.css?ver=4.2.2' type='text/css' media='all' />
<link rel='stylesheet' id='login-css' href='http://kseek.com.my/wp-admin/css/login.min.css?ver=4.2.2' type='text/css' media='all' />
<link rel="apple-touch-icon" sizes="57x57" href="/wp-content/uploads/fbrfg/apple-touch-icon-57x57.png">
<link rel="apple-touch-icon" sizes="114x114" href="/wp-content/uploads/fbrfg/apple-touch-icon-114x114.png">
<link rel="apple-touch-icon" sizes="72x72" href="/wp-content/uploads/fbrfg/apple-touch-icon-72x72.png">
<link rel="apple-touch-icon" sizes="144x144" href="/wp-content/uploads/fbrfg/apple-touch-icon-144x144.png">
<link rel="apple-touch-icon" sizes="60x60" href="/wp-content/uploads/fbrfg/apple-touch-icon-60x60.png">
<link rel="apple-touch-icon" sizes="120x120" href="/wp-content/uploads/fbrfg/apple-touch-icon-120x120.png">
<link rel="apple-touch-icon" sizes="76x76" href="/wp-content/uploads/fbrfg/apple-touch-icon-76x76.png">
<link rel="apple-touch-icon" sizes="152x152" href="/wp-content/uploads/fbrfg/apple-touch-icon-152x152.png">
<link rel="apple-touch-icon" sizes="180x180" href="/wp-content/uploads/fbrfg/apple-touch-icon-180x180.png">
<link rel="shortcut icon" href="/wp-content/uploads/fbrfg/favicon.ico">
<link rel="icon" type="image/png" href="/wp-content/uploads/fbrfg/favicon-192x192.png" sizes="192x192">
<link rel="icon" type="image/png" href="/wp-content/uploads/fbrfg/favicon-160x160.png" sizes="160x160">
<link rel="icon" type="image/png" href="/wp-content/uploads/fbrfg/favicon-96x96.png" sizes="96x96">
<link rel="icon" type="image/png" href="/wp-content/uploads/fbrfg/favicon-16x16.png" sizes="16x16">
<link rel="icon" type="image/png" href="/wp-content/uploads/fbrfg/favicon-32x32.png" sizes="32x32">
<meta name="msapplication-TileColor" content="#da532c">
<meta name="msapplication-TileImage" content="/wp-content/uploads/fbrfg/mstile-144x144.png">
<meta name="msapplication-config" content="/wp-content/uploads/fbrfg/browserconfig.xml"><meta name='robots' content='noindex,follow' />
</head>
<body class="login login-action-login wp-core-ui locale-en-us">
<div id="login">
<h1><a href="https://wordpress.org/" title="Powered by WordPress" tabindex="-1">K SEE K architect</a></h1>
<form name="loginform" id="loginform" action="http://kseek.com.my/wp-login.php" method="post">
<p>
<label for="user_login">Username<br />
<input type="text" name="log" id="user_login" class="input" value="" size="20" /></label>
</p>
<p>
<label for="user_pass">Password<br />
<input type="password" name="pwd" id="user_pass" class="input" value="" size="20" /></label>
</p>
<p class="forgetmenot"><label for="rememberme"><input name="rememberme" type="checkbox" id="rememberme" value="forever" /> Remember Me</label></p>
<p class="submit">
<input type="submit" name="wp-submit" id="wp-submit" class="button button-primary button-large" value="Log In" />
<input type="hidden" name="redirect_to" value="http://kseek.com.my/wp-admin/" />
<input type="hidden" name="testcookie" value="1" />
</p>
</form>
<p id="nav">
<a href="http://kseek.com.my/wp-login.php?action=lostpassword" title="Password Lost and Found">Lost your password?</a>
</p>
<script type="text/javascript">
function wp_attempt_focus(){
setTimeout( function(){ try{
d = document.getElementById('user_login');
d.focus();
d.select();
} catch(e){}
}, 200);
}
wp_attempt_focus();
if(typeof wpOnload=='function')wpOnload();
</script>
<p id="backtoblog"><a href="http://kseek.com.my/" title="Are you lost?">← Back to K SEE K architect</a></p>
</div>
<div class="clear"></div>
</body>
</html>
>>>
|
How to get all characters between 2 characters in a string in python
Question: I am trying to scrap some data from a website, and below is a long string that
I have managed to get.
var playerlist=["Roger Federer", "Rainer Schuettler", "Dominik Hrbaty", "Thomas Muster", "Andy Roddick", "Nikolay Davydenko", "Tommy Haas", "Jarkko Nieminen", "Arnaud Clement", "Ivan Ljubicic", "David Ferrer", "Nicolas Massu", "Tommy Robredo", "Lleyton Hewitt", "Filippo Volandri", "Olivier Rochus", "Kevin Kim", "Juan Ignacio Chela", "Juan Carlos Ferrero", "Jimmy Connors", "Mikhail Youzhny", "Ruben Ramirez Hidalgo", "Rafael Nadal"]
Above is not a javascript list, it is a String.
I want to create a list of all player names from this string. So I have to
extract all the substrings between " " and add it to a list. Alternatively if
I can somehow convert this string as it is to a list or an array, it would be
great.
Can someone suggest how can we do this in python?
Answer: You can use
[`ast.literal_eval`](https://docs.python.org/3/library/ast.html#ast.literal_eval)
>>> s = 'var playerlist=["Roger Federer", "Rainer Schuettler", "Dominik Hrbaty", "Thomas Muster", "Andy Roddick", "Nikolay Davydenko", "Tommy Haas", "Jarkko Nieminen", "Arnaud Clement", "Ivan Ljubicic", "David Ferrer", "Nicolas Massu", "Tommy Robredo", "Lleyton Hewitt", "Filippo Volandri", "Olivier Rochus", "Kevin Kim", "Juan Ignacio Chela", "Juan Carlos Ferrero", "Jimmy Connors", "Mikhail Youzhny", "Ruben Ramirez Hidalgo", "Rafael Nadal"]'
>>> import ast
>>> start = s.index('[')
>>> ast.literal_eval(s[start:])
['Roger Federer', 'Rainer Schuettler', 'Dominik Hrbaty', 'Thomas Muster', 'Andy Roddick', 'Nikolay Davydenko', 'Tommy Haas', 'Jarkko Nieminen', 'Arnaud Clement', 'Ivan Ljubicic', 'David Ferrer', 'Nicolas Massu', 'Tommy Robredo', 'Lleyton Hewitt', 'Filippo Volandri', 'Olivier Rochus', 'Kevin Kim', 'Juan Ignacio Chela', 'Juan Carlos Ferrero', 'Jimmy Connors', 'Mikhail Youzhny', 'Ruben Ramirez Hidalgo', 'Rafael Nadal']
As Steve mentions below in the comments, it is better to use,
[`json.loads`](https://docs.python.org/2/library/json.html#json.loads)
>>> import json
>>> json.loads(s[start:])
[u'Roger Federer', u'Rainer Schuettler', u'Dominik Hrbaty', u'Thomas Muster', u'Andy Roddick', u'Nikolay Davydenko', u'Tommy Haas', u'Jarkko Nieminen', u'Arnaud Clement', u'Ivan Ljubicic', u'David Ferrer', u'Nicolas Massu', u'Tommy Robredo', u'Lleyton Hewitt', u'Filippo Volandri', u'Olivier Rochus', u'Kevin Kim', u'Juan Ignacio Chela', u'Juan Carlos Ferrero', u'Jimmy Connors', u'Mikhail Youzhny', u'Ruben Ramirez Hidalgo', u'Rafael Nadal']
|
Writing a dict into a png file
Question: I'm a beginner on python and only have rudiments of this language, the
question might not be a hard one but it's bogging me down.
Now I have a 'dict' data structure, let's assume it being {(0,0): 'red'}, just
one element.
I want to draw a unit square of red color centered at point (0,0) on the 2D
plane, and output the result as a .png file. Once this is down, one can easily
do the case of many many more points in the dict.
I think the code should be very simple( it's best not to use libs, for example
matplotlib cairo .. etc), but I do not know how to interact with graphics, can
anyone give me a hint?
I googled but the results mostly are matplotlib, pyplot... that use lib files,
I think there must be a simple solution with only plain python code, so I post
here for help.
Answer: Personally I find cairo the easiest one. All you need is to set up canvas and
fill it with shapes. For a rectangular you will need its X, Y position as
starting points and width and height to complete drawing. Colors are used in
rgb float. You will have to convert named colors to rgb if you want to use
them.
I made an example for you:
#!/usr/bin/python
# -*- coding: utf-8 -*-
import cairo
# You need colors in rgb floats
Dict= {(70,60): (1,1,0), (100,90): (0,1,0), (130,120): (0,0,1)}
your_dict={(0,0): (1,0,0)}
radius=10 # The radius of the dot
w=100 # width of the square
h=100 # height of the square
WIDTH, HEIGHT = 200, 200 # Canvas size
surface = cairo.ImageSurface (cairo.FORMAT_ARGB32, WIDTH, HEIGHT)
context = cairo.Context (surface)
# Background Neutral Gray ----------
context.set_source_rgb(0.25, 0.25, 0.25)
context.rectangle(0, 0, WIDTH, HEIGHT)
context.fill()
# Your Square -----------------------
for e in your_dict:
posX = e[0]
posY = e[1]
r = your_dict[e][0]
g = your_dict[e][1]
b = your_dict[e][2]
context.set_source_rgb(r, g, b) # rgb color
context.rectangle(posX, posY, w, h)
context.fill()
# White Example Circle -------------------
context.set_source_rgb(1, 1, 1) # rgb color
context.arc(20, 20, 10.0, 0, 360)
context.fill()
# Dots from Dict -------------------
for e in Dict:
posX = e[0]
posY = e[1]
r = Dict[e][0]
g = Dict[e][1]
b = Dict[e][2]
context.set_source_rgb(r, g, b) # rgb color
context.arc(posX, posY, radius, 0, 360)
context.fill()
surface.write_to_png ("img.png") # Output to PNG
You will get an image: <http://oi59.tinypic.com/2yy2iv7.jpg>
|
Compare consecutive columns of a file and return the number of non-matching elements
Question: I have a text file which looks like this:
# sampleID HGDP00511 HGDP00511 HGDP00512 HGDP00512 HGDP00513 HGDP00513
M rs4124251 0 0 A G 0 A
M rs6650104 0 A C T 0 0
M rs12184279 0 0 G A T 0
I want to compare the consecutive columns and return the number of matching
elements. I want to do this in Python. Earlier, I did it using Bash and AWK
(shell scripting), but its very slow, as I have huge data to process. I
believe Python would be a faster solution to this. But, I am very new to
Python and I already have something like this:
for line in open("phased.txt"):
columns = line.split("\t")
for i in range(len(columns)-1):
a = columns[i+3]
b = columns[i+4]
for j in range(len(a)):
if a[j] != b[j]:
print j
which is obviously not working. As I am very new to Python, I don't really
know what changes to make to get this to work. (This is code is completely
wrong and I guess I could use difflib, etc. But, I have never proficiently
coded in Python before, so, skeptical to proceed)
I want to compare and return the number of non matching elements in each
column(starting from the third) to every other column in the file. I have 828
columns in totality. Hence I would need 828*828 number of outputs. (You can
think of a n*n matrix where the (i,j)th element would be the number of non
matching elements between them. My desired output in case of the above snippet
would be:
3 4: 1
3 5: 3
3 6: 3
......
4 6: 3
..etc
Any help on this would be appreciated. Thanks.
Answer: I highly recommend you use pandas for this rather than writing your own code:
import numpy as np
import pandas as pd
df = pd.read_csv("phased.txt")
match_counts = {(i,j):
np.sum(df[df.columns[i]] != df[df.columns[j]])
for i in range(3,len(df.columns))
for j in range(3,len(df.columns))}
match_counts
{(6, 4): 3,
(4, 7): 2,
(4, 4): 0,
(4, 3): 3,
(6, 6): 0,
(4, 5): 3,
(5, 4): 3,
(3, 5): 3,
(7, 7): 0,
(7, 5): 3,
(3, 7): 2,
(6, 5): 3,
(5, 5): 0,
(7, 4): 2,
(5, 3): 3,
(6, 7): 2,
(4, 6): 3,
(7, 6): 2,
(5, 7): 3,
(6, 3): 2,
(5, 6): 3,
(3, 6): 2,
(3, 3): 0,
(7, 3): 2,
(3, 4): 3}
|
Django list rendered as string in template - cannot access list value
Question: New to Django so please bare with me.
_The problem :_ I try to iterate over a list which is the result of the
selection of multiple items in a form (use of forms.MultipleChoiceField). This
is then saved in my db using models.Charfield and passed from the view to the
template through context_dict `(context_dict['attachment'] =
attachment.pieces_jointes)` However I think that it is not saved as a list but
as a string. Instead of:
[u'essai document', u'essai document 2', u'essai document5'],
I think I have (because of model field type):
"[u'essai document', u'essai document 2', u'essai document5']"
Indeed, in my template if I type :
{% for attachment in attachments %}
{{attachment.pieces_jointes.1}}
{% endfor %}
I get for that record:
u
and not :
essai document 2
For your information, if I open the admin and look at the value recorded I
have :
[u'essai document', u'essai document 2', u'essai document5']
I have tried to get rid of the possible "" which could be around the list but
I haven't succeeded. Can anyone explain my how I can turn that string back
into a list and iterate over it in my template? Thanks
A bit of code as requested:
models.py
class Document (models.Model):
dpseudo = models.ForeignKey(Identite)
dnom = models.CharField(max_length=128, unique=False)
dphoto = models.ImageField(upload_to='profile_document', blank=False)
ddate_ajout = models.CharField(max_length=128, unique=False)
slug = models.SlugField(unique=True)
def save(self, *args, **kwargs):
if not self.id:
self.slug = slugify(self.dpseudo) + slugify(self.dnom) + slugify(self.ddate_ajout)
super(Document, self).save(*args, **kwargs)
def __unicode__(self): #For Python 2, use __str__ on Python 3
return self.dnom
class Attachment (models.Model):
name = models.CharField(max_length=128, unique=True)
date_creation = models.CharField(max_length=128, unique=False)
statut = models.CharField(max_length=128, unique=False)
pieces_jointes = models.CharField(max_length=128, unique=False)
slug = models.SlugField(unique=True)
def save(self, *args, **kwargs):
if not self.id:
self.slug = slugify(self.name)
super(Attachment, self).save(*args, **kwargs)
def __unicode__(self): #For Python 2, use __str__ on Python 3
return self.name
views.py
import ast
def attacher(request):
piece_list = Attachment.objects.all()
attachment_list =[ast.literal_eval(i) for i in Attachment.objects.values_list('pieces_jointes', flat=True)]
context_dict = {'pieces': piece_list, 'nom_pieces_jointes' : attachment_list}
return render(request, 'job/attacher.html', context_dict)
forms.py
class AttachmentForm(forms.ModelForm):
name = forms.CharField(max_length=128, help_text="Please enter the name.")
pieces_jointes = forms.MultipleChoiceField(choices=[])
def __init__(self, *args, **kwargs):
super(AttchmentForm, self).__init__(*args, **kwargs)
self.fields['pieces_jointes'].choices = [(document.dnom, document.dnom) for document in Document.objects.all()]
class Meta:
model = Attchment
fields = ('name','pieces_jointes')
As advised, I used ast.literal_eval() in my views but I get an error :
unexpected EOF while parsing (, line 1)
Answer: As you said you have saved `attachment.pieces_jointes` as string :
"[u'essai document', u'essai document 2', u'essai document5']"
you can use `ast.literal_eval` in your `view` to pass the list in template:
>>> import ast
>>> l=ast.literal_eval("[u'essai document', u'essai document 2', u'essai document5']")
>>> l[1]
u'essai document 2'
|
Python: 'unicode' object has no attribute 'iteritems'
Question: In my app using Python 2.6.9 I have this incoming JSON as a unicode string:
{"devices": "{1540702298: u\"{'on': u'True', 'group': '2', 'time': u'2015-06-04 16:37:52', 'value': u'74.1', 'lastChange': u'2015-06-05 09:28:10'}\"}"}
I have tried in various ways to parse it but I still get the same error...
For example:
a = unicode({"devices": "{1540702298: u\"{'on': u'True', 'group': '2', 'energyAccumBaseTime': u'2015-06-04 16:37:52', 'sensorValueRaw': u'74.1', 'lastChange': u'2015-06-05 09:28:10', 'energyAccumTotal': u'1.3', 'sensorValueUi': u'74.1'}\"}"})
b = json.loads(a)
print b['devices'] # all good I get the contents...
but when I do...
for k, v in b['devices'].iteritems():
print k
I get the error:
> 'unicode' object has no attribute 'iteritems'
How can I parse this incoming JSON in full?
Answer: The outer object may be JSON, but it contains a string that itself is a Python
dictionary literal, containing Unicode literals as values.
Someone did this:
python_dictionary = {}
python_dictionary[integer_key] = str(another_dictionary)
outer_object {"devices": str(python_dictionary)}
before encoding the `outer_object` to JSON. Each value in that dictionary is
itself another string representing a Python dictionary, and those dictionaries
contain more strings representing dictionaries, like so many [Matryoshka
dolls](http://en.wikipedia.org/wiki/Matryoshka_doll).
You can use the [`ast.literal_eval()`
function](https://docs.python.org/2/library/ast.html#ast.literal_eval) to turn
that back into Python objects:
import ast
import json
yourobject = json.loads(jsondata)
dictionary = ast.literal_eval(yourobject['devices'])
for key, nested in dictionary.iteritems():
nested = ast.literal_eval(nested)
print key, nested
but you should really fix whatever produced the string to avoid storing the
nested dictionary as a string. Note that the keys in that nested dictionary
are integers; those would have to be converted to strings to work in JSON.
Demo:
>>> import json
>>> import ast
>>> jsondata = r'''{"devices": "{1540702298: u\"{'on': u'True', 'group': '2', 'time': u'2015-06-04 16:37:52', 'value': u'74.1', 'lastChange': u'2015-06-05 09:28:10'}\"}"}'''
>>> yourobject = json.loads(jsondata)
>>> type(yourobject['devices'])
<type 'unicode'>
>>> ast.literal_eval(yourobject['devices'])
{1540702298: u"{'on': u'True', 'group': '2', 'time': u'2015-06-04 16:37:52', 'value': u'74.1', 'lastChange': u'2015-06-05 09:28:10'}"}
>>> dictionary = ast.literal_eval(yourobject['devices'])
>>> dictionary[1540702298]
u"{'on': u'True', 'group': '2', 'time': u'2015-06-04 16:37:52', 'value': u'74.1', 'lastChange': u'2015-06-05 09:28:10'}"
>>> type(dictionary[1540702298])
<type 'unicode'>
>>> for key, nested in dictionary.iteritems():
... nested = ast.literal_eval(nested)
... print key, nested
...
1540702298 {'on': u'True', 'lastChange': u'2015-06-05 09:28:10', 'group': '2', 'value': u'74.1', 'time': u'2015-06-04 16:37:52'}
|
How to write a dictionary with multiple keys, each with multiple values to a csv in Python?
Question: I have a dictionary that looks like this...
cla_1results= {"Tom":[1,7,4],"Dunc":[3,9,4],"Jack":[1,3,5]}
I want to write this dictionary to a csv so that it is in the following format
Don't have the rep to post images but it would be something like this...
Tom, 1, 7, 4
Dunc 3, 9, 4
Jack 1, 3, 5
Nothing I've tried has worked. My recent effort is below but I'm a real
beginner with Python and programming in general.
import csv
cla_1results= {"Tom":[1,7,4],"Dunc":[3,9,4],"Jack":[1,3,5]}
cla_2results = {"Jane":[1,7,4],"Lynda":[3,9,4],"Dave":[1,3,5]}
cla_3results = {"Gemma":[1,7,4],"Steve":[3,9,4],"Jay":[1,3,5]}
b = open ('test.csv','w')
a = csv.writer(b)
data = cla_1results= {"Tom":[1,7,4],"Dunc":[3,9,4],"Jack":[1,3,5]}
a.writerows(data)
b.close()
which unfortunately only gives me:
T, o, m
D, u, n, c
J, a, c, k
etc
Answer: This should work, you just needed a list to generate csv file, so it can be
generated on the fly as well.
import csv
cla_1results= {"Tom":[1,7,4],"Dunc":[3,9,4],"Jack":[1,3,5]}
with open('test.csv', 'wb') as csvfile:
writer = csv.writer(csvfile, delimiter=',')
for key,value in cla_1results.iteritems():
writer.writerow([key]+value)
|
Which dynamically created object called the function?
Question: I am making a python app with a Tkinter GUI. So far it has some dynamically
created listboxes which I will link all to one scrollbar. I need a way to let
`yscroll()` know which listbox has been scrolled. Passing the `i` variable to
`yscroll()` does not work.
from Tkinter import *
class MyApp(Tk):
def __init__(self):
Tk.__init__(self)
self.title(' - My App - ')
self.listboxes = []
for i in xrange(5):
lb = Listbox(self, yscrollcommand=lambda i, *args: self.yscroll(i, *args))
for x in xrange(30):
lb.insert('end', x)
lb.pack(fill='y', side='left')
self.listboxes.append( lb )
self.scrollbar = Scrollbar(self, orient='vertical')
self.scrollbar.pack(side='right', fill='y')
def yscroll(self, i, *args):
print i
print args
ma = MyApp()
ma.mainloop()
Answer: It seems like the [usual recipe for using a variable from a loop in a
lambda](http://stackoverflow.com/a/19837683/1639625) does not work properly
when used together with parameter unpacking with `*args`. But since `*args`
seems to always consist of two values in this case (the beginning and the end
of the viewport, unless I'm mistaken), you could rewrite your `lambda` like
this:
lb = Listbox(self, yscrollcommand = lambda x, y, i=i: self.yscroll(i, x, y))
Or you can create a sort of "meta lambda", creating a lambda with the correct
value for `i`
make_callback = lambda i: lambda *args: self.yscroll(i, *args)
lb = Listbox(self, yscrollcommand = make_callback(i))
Both will bind `i` to the value of `i` in the iteration when the `lambda` was
defined.
|
Unable to zipfiles within folders using Python
Question: I have multiple folders within a directory (D:/zptest). Each folder has many
files. I am trying to zip all these files with in that folder and save the
file in the same folder with the "foldername.zip" I have written a script for
this but unfortunately it's throwing the following error
PermissionError: [Errno 13] Permission denied:
Can some body help me?
I am using the following code
#!/usr/bin/env python
import os, zipfile
from pathlib import Path
loc=r'D:\zipfilelist'
p=Path(r'D:\zptest')
for x in p.iterdir():
x1=str(x)
print("Processing: " + x1)
dirs=os.listdir(x1)
for file in dirs:
file=os.path.join(x1,file)
zip = zipfile.ZipFile(, "a", zipfile.ZIP_DEFLATED)
zip.write(file)
zip.close()
Answer: Thanks for all your help. I was able to complete a working code.
#!/usr/bin/env python
import os, zipfile, datetime, time
from pathlib import Path
p=Path(r'V:\NAR_ARCHIVE')
for x in p.iterdir():
x1=str(x)
print("Processing: " + x1)
#zipfilename = "%s.zip" % (x.stem)
loc=r'Y:\StorageReports\NAR_Zips'
loc=loc + '\\' + x.stem + '.zip'
print (loc)
print(x.stem)
dirs=os.listdir(x1)
#print(dirs)
for file in dirs:
sdate=datetime.datetime(2015,5,30)
edate=datetime.datetime(2015,6,7)
file=os.path.join(x1,file)
crtime=time.ctime(os.path.getmtime(file))
d1=datetime.datetime.strptime(crtime,"%a %b %d %H:%M:%S %Y")
if d1<edate and d1>sdate:
file=os.path.join(x1,file)
print(file)
#logFile = open(r"Y:\StorageReports\NAR_Zips\logfile.log","a")
#print >> logFile,message
zip = zipfile.ZipFile(loc, "a", zipfile.ZIP_DEFLATED)
zip.write(file)
zip.close()
|
print_matrix of munkres library python throws an exception on matrix containing zeroes
Question:
Lowest cost through this matrix:
Traceback (most recent call last):
File "muncre.py", line 8, in <module>
print_matrix(matrix, msg='Lowest cost through this matrix:')
File "/usr/lib/python2.7/dist-packages/munkres.py", line 730, in print_matrix
width = max(width, int(math.log10(val)) + 1)
ValueError: math domain error
When the matrix is containing zero in any of the rows, the above error is
thrown. How can I fix it?
This is the piece of code in python:
from munkres import Munkres, print_matrix
matrix = [[6, 9, 1],
[10, 9, 2],
[0,8,7]]
m = Munkres()
indexes = m.compute(matrix)
print_matrix(matrix, msg='Lowest cost through this matrix:')
total = 0
for row, column in indexes:
value = matrix[row][column]
total += value
print '(%d, %d) -> %d' % (row, column, value)
print 'total cost: %d' % total
I installed the library munkres using the following command in Ubuntu:
**sudo apt-get install python-munkres**
Answer: This really looks like a bug with the munkres library. The print_matrix is
just a "convenience" function and I'd suggest filing a bug report and in the
interim just replacing it with something like the following (which is just
their code with a fix to avoid trying to apply 0 or negative numbers to the
logarithm). What there were trying to do is make it properly space each column
to be the largest width for a number. Note that if you pass in negative
numbers, this may have an off by 1 issue, but on the other hand, if you have
negative costs, you may have bigger issues.
def print_matrix(matrix, msg=None):
"""
Convenience function: Displays the contents of a matrix of integers.
:Parameters:
matrix : list of lists
Matrix to print
msg : str
Optional message to print before displaying the matrix
"""
import math
if msg is not None:
print(msg)
# Calculate the appropriate format width.
width = 1
for row in matrix:
for val in row:
if abs(val) > 1:
width = max(width, int(math.log10(abs(val))) + 1)
# Make the format string
format = '%%%dd' % width
# Print the matrix
for row in matrix:
sep = '['
for val in row:
sys.stdout.write(sep + format % val)
sep = ', '
sys.stdout.write(']\n')
|
How to read xml directly from URLs with scrapy/python
Question: In Scrapy you will have to define `start_url`s. But how can I crawl from other
urls as well?
Up to now I have a login script which logs into a webpage. After logging in, I
want to extract xml from different urls.
import scrapy
class LoginSpider(scrapy.Spider):
name = 'example'
start_urls = ['login page']
urls = ['url','url']
def parse(self, response):
return scrapy.FormRequest.from_response(
response,
formdata={'UserName': '', 'Password': ''},
callback=self.check_login_response
)
def check_login_response(self, response):
# check login succeed before going on
if "incorrect" in response.body:
self.log("Login failed", level=scrapy.log.ERROR)
return
How is it possible to crawl data from the urls defined in the urls array?
Answer: You need to `yield`
[`Request`](http://doc.scrapy.org/en/latest/topics/request-
response.html#scrapy.http.Request) instances to the other URLs:
def check_login_response(self, response):
# check login succeed before going on
if "incorrect" in response.body:
self.log("Login failed", level=scrapy.log.ERROR)
return
for url in list_or_urls:
yield Request(url, callback=self.parse_other_url)
def parse_other_url(self, response):
# ...
|
Interactive python matplotlib
Question: python noob here. I'm trying to recreate this example
from mpl_toolkits.mplot3d import Axes3D
from matplotlib.collections import PolyCollection
import matplotlib.pyplot as plt, mpld3
from matplotlib import colors
from matplotlib.colors import colorConverter
import matplotlib.animation as animation
import numpy as np
fig = plt.figure()
ax = fig.gca(projection='3d')
cc = lambda arg: colorConverter.to_rgba(arg, alpha=0.6)
xs = np.arange(0, 10, 0.4)
verts = []
zs = [0.0, 1.0, 2.0, 3.0]
for z in zs:
ys = np.random.rand(len(xs))
ys[0], ys[-1] = 0, 0
verts.append(list(zip(xs, ys)))
poly = PolyCollection(verts, facecolors = [cc('r'), cc('g'), cc('b'),
cc('y')])
poly.set_alpha(0.7)
ax.add_collection3d(poly, zs=zs, zdir='y')
ax.set_xlabel('X')
ax.set_xlim3d(0, 10)
ax.set_ylabel('Y')
ax.set_ylim3d(-1, 4)
ax.set_zlabel('Z')
ax.set_zlim3d(0, 1)
mpld3.show()
I wanted to save the interactive plot (and send it to someone who doesn't use
python) so mpld3.show() seems like it could do the trick. Only I keep getting
this error
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Library/Python/2.7/site-packages/mpld3/_display.py", line 338, in show
html = fig_to_html(fig, **kwargs)
File "/Library/Python/2.7/site-packages/mpld3/_display.py", line 236, in fig_to_html
figure_json=json.dumps(figure_json),
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 243, in dumps
return _default_encoder.encode(obj)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 207, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 270, in iterencode
return _iterencode(o, 0)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 184, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: array([ 0., 10.]) is not JSON serializable
I understand that this is because _something_ is an np array not a list, but
when I
type(verts)
I get
<type 'list'>
So I'm not sure what that "array([ 0., 10.])" is/ how to fix this. Please
include an explanation of how to extract/ manipulate objects of type
<class 'mpl_toolkits.mplot3d.art3d.Poly3DCollection'>
Excuse my noobiness. Thanks y'all.
Answer: According to the [mpld3 github](https://github.com/jakevdp/mpld3/issues/223),
"3D plots are not currently supported in mpld3", and thus produces the error
you're seeing
I ran across your question because I am looking for the same solution (the
ability to share an interactive 3D matplotlib plot with someone who doesn't
have Python). I realize this is not an answer, but I thought it was still
worth sharing? (I'm also a noob, so I can't even comment on your question)
|
Python Library for Boyer-Myrvold planarity test or Kuratowski subgraph identification
Question: I am working with NetworkX Graphs in Python and I would like to find the
Kuratowski subgraphs of any given graph which I have.
The Boyer-Myrvold planar graph testing algorithm can return an existing
Kuratowski subgraph if the graph is not planar (O(n) in the number of vertices
n), so I was hoping that there might already be an implementation of that
algorithm or of a similar algorithm in Python. I have been so far unable to
find one and I am slightly reluctant at having to re-implement it from the
original research paper.
It is even better if it can easily interface with NetworkX library for graphs.
Answer: There is a Python wrapper for part of of John Boyer's planarity code
(<https://code.google.com/p/planarity/>) that might be what you are looking
for. It is at <https://github.com/hagberg/planarity>.
It has a NetworkX interface that allows you to test for planarity and find the
Kurotowski subgraphs if not. e.g.
<https://github.com/hagberg/planarity/blob/master/examples/networkx_interface.py>
import planarity
import networkx as nx
# Example of the complete graph of 5 nodes, K5
G=nx.complete_graph(5)
# K5 is not planar
print(planarity.is_planar(G)) # False
# find forbidden Kuratowski subgraph
K=planarity.kuratowski_subgraph(G)
print(K.edges()) # K5 edges
|
How to set the marker color when using geojson.Feature
Question: I am using python and my code is like:
from geojson import Feature, FeatureCollection
import json
import sys, pymongo
db = pymongo.MongoClient(host = '..........').database
coll_name = sys.argv[1]
point_list = []
citymap_cursor = db[coll_name].find()
for doc in citymap_cursor:
point_list.append(Feature(geometry=doc['point_latlng']))
with open('/path to/%s.json' % coll_name, 'w+') as outfile:
json.dump(FeatureCollection(point_list), outfile)
By this code I got a batch of points and I can use geojson.io to visualize the
points. Now these point markers are grey on geojson.io but I want them to be
red. I want to know whether these is an attribute about color in
geojson.Feature so that I can adjust the marker color?
Answer: Yes, you can manipulate the marker colors with a `marker-color` key inside the
`properties` object. You pass it a hex color like `{"marker-color":"#FFF"}`. I
assume you will be doing this inside your `for doc in citymap_cursor:` loop -
something like
`point_list.append(Feature(geometry=doc['point_latlng'],properties={'marker-
color':'#FFF'}))`
|
Importing pymongo on OpenShift
Question: My OpenShift application, which is written in Python with a MongoDB database,
is failing to import pymongo. My logs say
import pymongo
[Fri Jun 05 12:11:01 2015] [error] [client 127.10.149.1] File "/var/lib/openshift/55706c785973ca947100005a/python/virtenv/lib/python2.7/site-packages/pymongo/__init__.py", line 83, in <module>
[Fri Jun 05 12:11:01 2015] [error] [client 127.10.149.1] from pymongo.collection import ReturnDocument
[Fri Jun 05 12:11:01 2015] [error] [client 127.10.149.1] File "/var/lib/openshift/55706c785973ca947100005a/python/virtenv/lib/python2.7/site-packages/pymongo/collection.py", line 28, in <module>
[Fri Jun 05 12:11:01 2015] [error] [client 127.10.149.1] from pymongo import (common,
[Fri Jun 05 12:11:01 2015] [error] [client 127.10.149.1] ImportError: cannot import name common
I can't find any mention of "common" in the pymongo documentation. Any idea
what I need to do to fix this?
Answer: It was an installation problem.
To fix it, I logged in using ssh, uninstalled pymongo and bson, made sure bson
wasn't in requirements.txt, and pushed a change.
This did a clean install of pymongo.
|
Parallelism/Performance problems with Scrapyd and single spider
Question: # Context
I am running scrapyd 1.1 + scrapy 0.24.6 with a single "selenium-scrapy
hybrid" spider that crawls over many domains according to parameters. The
development machine that host scrapyd's instance(s?) is an OSX Yosemite with 4
cores and this is my current configuration:
[scrapyd]
max_proc_per_cpu = 75
debug = on
Output when scrapyd starts:
2015-06-05 13:38:10-0500 [-] Log opened.
2015-06-05 13:38:10-0500 [-] twistd 15.0.0 (/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python 2.7.9) starting up.
2015-06-05 13:38:10-0500 [-] reactor class: twisted.internet.selectreactor.SelectReactor.
2015-06-05 13:38:10-0500 [-] Site starting on 6800
2015-06-05 13:38:10-0500 [-] Starting factory <twisted.web.server.Site instance at 0x104b91f38>
2015-06-05 13:38:10-0500 [Launcher] Scrapyd 1.0.1 started: max_proc=300, runner='scrapyd.runner'
## EDIT:
Number of cores:
python -c 'import multiprocessing; print(multiprocessing.cpu_count())'
4
# Problem
I would like a setup to process 300 jobs simultaneously for a single spider
but scrapyd is processing 1 to 4 at a time regardless of how many jobs are
pending:
## EDIT:
CPU usage is not overwhelming :
## TESTED ON UBUNTU
I have also tested this scenario on a Ubuntu 14.04 VM, results are more or
less the same: a maximum of 5 jobs running was reached while execution, no
overwhelming CPU consumption, more or less the same time was taken to execute
the same amount of tasks.
Answer: The logs show that you have up to 300 processes allowed. The limit is
therefore further up the chain. My original suggestion was that it was the
serialization on your project as covered by [Running multiple spiders using
scrapyd](http://stackoverflow.com/questions/11390888/running-multiple-spiders-
using-scrapyd).
Subsequent investigation showed that the limiting factor was in fact the poll
interval.
|
Basic Flask Issue w/ Importing
Question: I'm following a Flask tutorial and am getting an import error. I have a file
called `run.py` which contains:
from app import app
app.run(debug = True)
When I run `./run.py`, I get:
Traceback (most recent call last):
File "./run.py", line 2, in <module>
from app import app
File "/Users/myName/Desktop/SquashScraper/app/__init__.py", line 1, in <module>
from flask import Flask
ImportError: cannot import name Flask
This seems similar to this issue:
`http://stackoverflow.com/questions/26960235/python3-cannot-import-name-flask`
So I attempted the checked solution by running:
virtualenv -p /usr/bin/python3 my_py3_env
Unfortunately, I get:
The executable /usr/bin/python3 (from --python=/usr/bin/python3) does not exist
Any ideas what may be happening here?
Thanks for the help, bclayman
Answer: If you want your virtual environment to be Python 3 but don't know the
installation directory, use `which python3`. Use that directory in your
`virtualenv -p [directory] my_py3_env` command to set up the Python 3 virtual
environment.
I sounds like your pip is installing to your Python 2.X directory. If you're
okay with that, you'll need to run the app either with `python2 run.py`,
`python2.X run.py` where `x` is your installed version, or change the symlink
of `python` in `/usr/bin/python` to your installation of Python 2.
[This](http://stackoverflow.com/questions/2812520/pip-dealing-with-multiple-
python-versions) question has some more information.
Regardless of the version of Python that you wish to use, you will need to
install Flask to _that_ version of Python. See
[this](http://stackoverflow.com/questions/10919569/how-to-pip-install-to-
specific-version-of-python) question for that.
|
Basic Flask: Adding Helpful Functions
Question: I've written a python script that works in terminal and am porting it to the
web using Flask. I've gone through parts of a tutorial (specifically:
`http://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-
world`)
I'm struggling a bit with where to put all the functions I use in my Python
script. The author () uses this code for a basic view:
def index():
user = {'nickname': 'Miguel'} # fake user
posts = [ # fake array of posts
{
'author': {'nickname': 'John'},
'body': 'Beautiful day in Portland!'
},
{
'author': {'nickname': 'Susan'},
'body': 'The Avengers movie was so cool!'
}
]
return render_template("index.html",
title='Home',
user=user,
posts=posts)
The problem is I don't have one function to call. I have 15 or so and it looks
like Flask only lets me call one function per view. So I'm not really sure
where to put all the helper functions that my "main" function will call.
Take the author's example code. If I had a function `getPosts()` that returns
an array of post objects, where would I put this?
Even if I'm allowed to put it under the route's main function (which I don't
think is allowed anyway), it seems like poor organization to do that.
Edit:
Here's my views.py file:
1 from flask import Flask
2 app = Flask(__name__)
3 from flask import render_template
4 from app import app
5 from app import helpfulFunctions
6
7 def testFunction():
8 return 5;
9
10 @app.route('/')
11 @app.route('/index')
12 def index():
13 #allPlayers = processGender(mainURL, menTeams)
14 myNum = testFunction()
15 return render_template('index.html', title = 'Home', user = user)
Answer: You're not restricted to one function per view -- you can have as many as you
want.
from flask import Flask
app = Flask(__name__)
def f():
...
def g():
...
@app.route('/index')
def index():
<here you can use f and g>
...
Functions don't need to correspond to views -- only the `@app.route(...)`
decorator makes it do that.
If you have a large number of other functions, it couldn't hurt to put them in
another file. Then you can `import` the file and use them as above.
|
make a full matrix output in python
Question: I have a matrix with 236 x 97 dimension. When I print the matrix in Python its
output isn't complete, having `.......` in the middle of matrix.
I tried to write the matrix to a test file, but the result is exactly same. I
can't post the screenshot because my reputation is not enough, and won't
appear correctly if I choose another markup option. Can anyone solve this?
* * *
def build(self):
self.keys = [k for k in self.wdict.keys() if len(self.wdict[k]) > 1]
self.keys.sort()
self.A = zeros([len(self.keys), self.dcount])
for i, k in enumerate(self.keys):
for d in self.wdict[k]:
self.A[i,d] += 1
def printA(self):
outprint = open('outputprint.txt','w')
print 'Here is the weighted matrix'
print self.A
outprint.write('%s' % self.A)
outprint.close()
print self.A.shape
Answer: The problem is that you're specifically saving the `str` representation to a
file with this line:
> `outprint.write('%s' % self.A)`
Which explicitly casts it to a string (`%s`) --- generating the abridged
version you're seeing.
There are lots of ways to write the entire matrix to output, one easy option
would be to use
[numpy.savetxt](http://docs.scipy.org/doc/numpy/reference/generated/numpy.savetxt.html),
for example:
import numpy
numpy.savetxt('outputprint.txt', self.A)
|
Python regex for diffstat output
Question: I would like to match the following strings using python regex and extract the
numbers.
1 file changed, 1 insertion(+), 1 deletion(-)
2 files changed, 10 insertions(+), 10 deletions(-)
1 file changed, 1 insertion(+)
1 file changed, 2 deletions(-)
So i though to use the named groups in python regex and look ahead patterns.
But that is not working as expected.
#!/usr/bin/python
import re
pat='\s*(\d+).*changed,\s+(\d*)(?P<in>=\s+insertion).*(\d+)(?P<del>=\s+deletion.*')
diff_stats = re.compile(pat)
obj = diff_stats.match(line)
Answer: Remove `=` from named capture group.. Also.. your last group is not closed!
\s*(\d+).*changed,\s+(\d*)(?P<in>\s+insertion).*(\d+)(?P<del>\s+deletion).*
↑ ↑ ↑
See [DEMO](https://regex101.com/r/aD2rI1/15)
**Edit:** Improved regex for `+` and `-` too and named capture of digits:
\s*(\d+)\s+files?\s+changed,\s*((?P<in>\d+)\s*(insertions?)\([+-]\))?,?\s*((?P<del>\d+)\s*(deletions?)\([+-]\))?
See [DEMO](https://regex101.com/r/aD2rI1/19)
|
Python 2.7 display jpeg image contained in zip file
Question: I have a set of jpeg files in a zip archive. I would like to display a member
jpeg image in a Tkinter widget.
I'm having trouble creating an Image object. I have tried feeding the output
of ZipFile.open() and ZipFile.read() to Image() and PhotoImage(), all of which
result in the same error message: "UnsupportedOperation: seek".
[Documentation](http://effbot.org/imagingbook/image.htm) for Image.open()
states that if a file object is given as the argument, the file object must
support the read, seek, and tell methods. Apparently the "file-like object"
returned by ZipFile.open() does not qualify.
zfile = zipfile.ZipFile(filename,'r')
...
filelikeobject = zfile.open(membername,'r')
image = Image.open(filelikeobject)
File "/usr/lib/python2.7/dist-packages/PIL/Image.py", line 1967, in open
fp.seek(0)
UnsupportedOperation: seek
I cannot find any relevant post dealing with zipped jpeg files. I know my zips
are well-formed because I can perform this operation, using the same files, in
Java and Perl (I am re-writing a large Java application in Python/Tk).
A brute force method would be to extract the member file to disk, and simply
call Image(pathname), but I'd rather do everything in memory.
Any help, please.
Answer: I was able to create a seekable memory file from a (nonseekable) ZipFile
object as follows:
from io import BytesIO
import zipfile
from PIL import Image, ImageTk
...
zfile = zipfile.ZipFile(filename,'r') # non-seekable
memberlist = zfile.namelist()
...
zfiledata = BytesIO(zfile.read(membername)) # seekable
image = Image.open(zfiledata) # image.show() will display
photo = ImageTk.PhotoImage(image)
Photo can then be used in any Tk widget which takes an image object (e.g.,
Canvas, Label, etc.)
On my first try of the above code, I got an error message about missing files.
Apparently ImageTk is not part of the standard 2.7 installation. Instructions
for installing it I found in a SO
[post](http://stackoverflow.com/questions/22788454/importerror-no-module-
named-imagingtk/22788542#22788542).
|
Create python dictionary by enumerate function
Question: I am looking for a simpler way to create this python dictionary. May I know if
enumerate function can help?
a_dict = {'a':0, 'b':1, 'c':2, ....}
Answer: you may simply use `string.ascii_lowercase` which is string of all lowercase
characters, then you `zip` the lowercase letters and list of number ranging
from `0` to `len(string.ascii_lowercase)` and then convert them to `dict`.
However you may want to use some other set of alphabet as
`string.ascii_letters`, `string.ascii_uppercase` , `string.letters`,
`string.punctuation`, etc.
You can easily filter the keys that you want in your dictionary either by
concatenating the above mentioned strings as
`string.ascii_lowercase+string.ascii_uppercase` would give us a string
containing first the 26 lowercase alphabets and then 26 uppercase alphabets,
you may also apply slicing methods to get desired set of characters, like
`string.ascii_lowercase[0:15]` would give you `"abcdefghijklmn"`
import string
alphabets = string.ascii_lowercase
print dict(zip(alphabets, range(len(alphabets))))
>>> {'a': 0, 'c': 2, 'b': 1, 'e': 4, 'd': 3, 'g': 6, 'f': 5, 'i': 8, 'h': 7, 'k': 10, 'j': 9, 'm': 12, 'l': 11, 'o': 14, 'n': 13, 'q': 16, 'p': 15, 's': 18, 'r': 17, 'u': 20, 't': 19, 'w': 22, 'v': 21, 'y': 24, 'x': 23, 'z': 25}
|
How to check if any sys.argv argument equals a specific string in Python
Question: In Python I would like to check if _any_ argument that has been passed to my
script equals "-h" (so that I can display a help banner and exit).
Should I loop through sys.argv values or is there a more simple way to achieve
this?
Answer:
import sys
def help_required():
return "-h" in sys.argv[1:]
|
Adding Pygame to PYTHONPATH
Question: * Windows 8 64 bit
* Python 3.4.3
* Pygame-1.9.2a0.win32-py3.4
I'm in the process of trying to install Pygame now. This computer has two
hard-drives, and I'm not sure if that means anything, but when I try and
install Pygame it defaults to my `D:\` drive. Python itself is installed on my
`C:\` drive however. [this](http://i.imgur.com/0XN8GJb.png) is what I see when
I try to install Pygame and [this](http://i.imgur.com/NAJMQjZ.png) is what I
think I should see when I install it (right?). That is a screenshot from a
video tutorial I was following.
So, I've copied all the files from the `pygame` folder to where it should
installed, which are `C:\Python34\Lib\site-packages` and
`C:\Python34\include`. Instead of getting the usual import error, I now get
[this error](http://i.imgur.com/f7rqHod.png). I've looked at a bunch of
similar problems and they all said that the problem probably is the
`PYTHONPATH`. So I've gone to the environment variables > system variables and
clicked `New`. `Variable name = PYTHONPATH` and `Variable_Value =
C:\Python34\Lib\site-packages\pygame;` Is this right?
When I type `import sys` \--> `print (sys.path)`, pygame does [show
up](http://i.imgur.com/kZRM616.png), but I still get an error.
Answer: I've had similar problem when installing pygame, Windows 8.1 wouldn't
recognise MinGW system variable, and leading to this pygame was never found.
What solved problem for me is <http://www.lfd.uci.edu/~gohlke/pythonlibs/> .
Here you can find unofficial wheels for many packages that won't install for
varoius reasons or simply don't work too well.
You simply need pip with version >= 6. Install the one with cp34, it is
corresponding with CPython 3.4.
|
parallel assignment variable from python to java (Pi algorithm)
Question: I would like to translate a python algorithm to Java, I have this source code
(using parallel asignment variable (doesn't exist in Java :( )
# -*- coding: cp1252 -*-
#! /usr/bin/env python
import sys
def main():
k, a, b, a1, b1 = 2L, 4L, 1L, 12L, 4L
while 1:
p, q, k = k*k, 2L*k+1L, k+1L
a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1
d, d1 = a/b, a1/b1
while d == d1:
output(d)
a, a1 = 10L*(a%b), 10L*(a1%b1)
d, d1 = a/b, a1/b1
def output(d):
sys.stdout.write(`int(d)`)
sys.stdout.flush()
#ecriture en continue du chiffre
pi = open("flypi.html", "a")
pi.write(`int(d)`)
pi.write("\n")
pi.close()
main()
So, first I recoded the same script without parallel assignement variable :
# -*- coding: cp1252 -*-
#! /usr/bin/env python
import sys
def main():
#k, a, b, a1, b1 = 2L, 4L, 1L, 12L, 4L
k = 2L
a = 4L
b = 1L
a1 = 12L
b1 = 4L
while 1:
#p, q, k = k*k, 2L*k+1L, k+1L
kk = k
p = kk*kk
q = 2L*kk+1L
k = kk+1L
#a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1
aa = a
bb = b
a = a1
b = b1
a1 = p*aa+q*a1
b1 = p*bb+q*b1
#d, d1 = a/b, a1/b1
d = a/b
d1 = a1/b1
while d == d1:
output(d)
#a, a1 = 10L*(a%b), 10L*(a1%b1)
a = 10L*(a%b)
a1 = 10L*(a1%b1)
#d, d1 = a/b, a1/b1
d = a/b
d1 = a1/b1
def output(d):
sys.stdout.write(`int(d)`)
sys.stdout.flush()
#ecriture en continue du chiffre
pi = open("flypi.html", "a")
pi.write(`int(d)`)
pi.write("\n")
pi.close()
main()
The output of these two script is the same:
31415926535897932384626433832795028841971693993751058209749445923078164062862089 (crt+c)
Now here is the script I made in Java (almost the same as the second python
script):
public static void cal(){
//int i = 0;
long d = 0;
long k = 2L;
long a = 4L;
long b = 1L, a1 = 12L, b1 = 4L;
long p = 0, q = 0, d1 = 0;
long aa = 0, bb = 0;
long kk = 0;
while(true){
kk = k;
p = kk*kk;
q = 2L*kk+1L;
k = kk+1L;
aa = a;
bb = b;
a = a1;
b = b1;
a1 = p*aa+q*a1;
b1 = p*bb+q*b1;
d = a/b;
d1 = a1/b1;
while(d == d1){
System.out.print(d);
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
a = 10L*(a%b);
a1 = 10L*(a1%b1);
d = a/b;
d1 = a1/b1;
}
//i++;
}
}
but the output is wrong :
31415926530000000001-100000000000000000100-300000101000000000000000000000000000000000000 (ctr+c)
Thank you, and sorry for the long post :)
EDIT: So yes it's a buffer overflow. I tried to implement BigInteger and it
works fine !! thank you !
Answer: In Python integers can be arbitrarily large. In Java a long consists of 64
bits and can therefore only store numbers smaller than about 2**64 / 2.
If a number is too big, the first bits of it are discarded and the most
significant bit that is not overwrites the sign of the integer, resulting in
negative numbers in mathematically impossible places.
Use BigInteger as ajb suggests or change your calculations in some way.
|
python dictionary get by value
Question: So my problem is how to get VALUE by key rather getting a pointer. I have the
following code, and I want to do sth to tempA without changing the value
within dictionary.
temp_keys=["a","b","c","d"]
temp_values=[[1,1],[2,2],[3,3],[4,4]]
temp=dict(zip(temp_keys,temp_values))
tempA=temp.get('a',temp.copy())
tempA.append(2)
print temp
output is:
{'a': [1, 1, 2], 'b': [2, 2], 'c': [3, 3], 'd': [4, 4]}
See the value of key "a" has been changed.
I want my variable temp unchanged,
{'a': [1, 1], 'b': [2, 2], 'c': [3, 3], 'd': [4, 4]}
Answer: I believe you are looking for deep copy
import copy
temp_keys=["a","b","c","d"]
temp_values=[[1,1],[2,2],[3,3],[4,4]]
temp=dict(zip(temp_keys,temp_values))
print temp
temp_copy = copy.deepcopy(temp)
temp_copy['a'].append(2)
print temp
Your `temp` will remain unchanged:
> {'d': [4, 4], 'b': [2, 2], 'c': [3, 3], 'a': [1, 1]} {'d': [4, 4], 'b': [2,
> 2], 'c': [3, 3], 'a': [1, 1]}
|
Reset password in Django
Question: I have view this tutorial <https://www.youtube.com/watch?v=z6pXNf2SzQQ> that
explain how to send mail to reset password, I have follow all steps but I have
the same error always: No module named 'my_app.views.django'; 'my_app.views'
is not a package. For this case my_app = melomanos. I have all templates for
Django reset password in my site templates folder.
**The complete site root is:**
**The error that shows is:** I know I have a missconfigured urls but I don't
understand how I can configure correctly. Thanks for your cooperation.
ImportError at /resetpassword/
No module named 'melomanos.views.django'; 'melomanos.views' is not a package
Request Method: GET
Request URL: http://localhost/resetpassword/
Django Version: 1.8.2
Exception Type: ImportError
Exception Value:
No module named 'melomanos.views.django'; 'melomanos.views' is not a package
Exception Location: C:\Python34\lib\importlib\__init__.py in import_module, line 109
Python Executable: C:\Python34\python.exe
Python Version: 3.4.3
Python Path:['c:\\labsoft',
'C:\\Python34\\lib\\site-packages\\psycopg2-2.6-py3.4-win-amd64.egg',
'C:\\Windows\\SYSTEM32\\python34.zip',
'C:\\Python34\\DLLs',
'C:\\Python34\\lib',
'C:\\Python34',
'C:\\Python34\\lib\\site-packages',
'labsoft/melomanos',
'/melomanos']
here is the codes:
**melomanos\urls.py**
from django.conf.urls import patterns, url, include
from django.views.generic.base import TemplateView
from django.contrib import admin
from .views import Buscar_view
admin.autodiscover()
urlpatterns = patterns('melomanos.views',
url(r'^admin/', include(admin.site.urls)),
url(r'^$','trabajos_all_view',name='url_index'),
url(r'^register/$','register_view',name='vista_registro'),
url(r'^login/$','login_view',name='vista_login'),
url(r'^logout/$','logout_view',name='vista_logout'),
url(r'^perfil/$','registro_view',name='vista_perfil'),
url(r'^publicar/$','trabajomusical_view', name='vista_publicar'),
url(r'^trabajos/$','trabajos_view',name='vista_trabajos'),
url(r'^trabajo/(?P<id_trabajo>.*)/$','solo_trabajo_view', name='vista_trabajo'),
url(r'^buscar/$',Buscar_view.as_view(),name='vista_buscar'),
url('', include('django.contrib.auth.urls')),
url(r'^resetpassword/passwordsent/$', 'django.contrib.auth.views.password_reset_done', name='password_reset_done'),
url(r'^resetpassword/$', 'django.contrib.auth.views.password_reset', name="reset_password"),
url(r'^reset/(?P<uidb36>[0-9A-Za-z]+)-(?P<token>,+)/$', 'django.contrib.auth.views.password_reset_confirm'),
url(r'^reset/done/$', 'django.contrib.auth.views.password_reset_complete'),
)
**The link at the login page:**
<p>Forgot your password?<a href="/resetpassword/">Reset Password</a></p>
**settings.py**
INSTALLED_APPS = (
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'melomanos',
)
Answer: On `melomanos\urls.py` you are using url prefix.
urlpatterns = patterns('melomanos.views',
url(r'^resetpassword/$', 'django.contrib.auth.views.password_reset', name="reset_password"),
)
So `/resetpassword/` is calling
`melomanos.views.django.contrib.auth.views.password_reset` instead of
`django.contrib.auth.views.password_reset`
For reset password view removing the prefix will solve this issue.
You may remove `resetpassword` from prefixed block and later add it without
prefix like
urlpatterns += patterns('',
url(r'^resetpassword/$', 'django.contrib.auth.views.password_reset', name="reset_password"),
)
|
Inheriting and aggregating class attributes
Question: A simple example:
class A:
attr = {'a': 1}
class B(A):
attr = {'b': 2} #overrides A.attr
What I want is a method to aggregate the dictionaries. I can think of just
these options:
1. Ignore that disconcerting feeling and copy everything by hand.
2. Manually adding the dictionaries:
class B(a):
attr = dict(list(six.iteritems(A.attr)) + list(six.iteritems({
'b': 2
})))
Note `'b': 2` must come second so its keys shadow `A`'s.
This must reference `A` explicitly (**is there some way to get this
with`super`?**). It also needs this kind of micro inheritance to be applied
manually.
3. This is also something that could be achieved with metaclasses. I've seen it [done in `DeclarativeFieldsMetaclass` in django](https://github.com/django/django/blob/master/django/forms/forms.py#L35). The idea is to have the metaclass handle dictionary merging for a specific attribute.
This is far more work. Also, as it introduces magic that doesn't normally
happen in python, this might be considered a poor option. I also prefer to not
use metaclasses unless necessary to avoid conflicts.
One major advantage is the user doesn't need to manually aggregate the
attribute data.
**Is there another way?**
**I'd like to know what others think of each approach with regard to good
programming practice.**
In my case I'm using a [`MultiModelForm` from django-
betterforms](http://django-
betterforms.readthedocs.org/en/latest/multiform.html), and have a base form
with just a few `ModelForm`s but want to extend it. I don't think the
inherited class should need to duplicate the `ModelForm`s in the
`form_classes` attribute from the parent.
Should it be up to the user to manage inheritance as in option 2 or should
`MultiModelForm` handle it automatically with a metaclass as in option 3? Are
there other issues with each option I haven't discussed?
Answer: You can do it using
[`dictionary.update()`](https://docs.python.org/2/library/stdtypes.html#dict.update)
function, which will add a new dictionary to an existing one
**Example**
>>> class A:
... attr = {'a': 1}
...
>>> class B(A):
... attr = dict(A.attr)
... attr.update({'b' : 2 })
...
>>>
>>> A.attr
{'a': 1}
>>> B.attr
{'a': 1, 'b': 2}
**What it does?**
* `attr = dict(A.attr)` returns a new dictionary from `A.attr`. This is important because if we write
attr = A.attr
we will end up updating the `attr` of `A` class instead of `B` class.
* `attr.update({'b' : 2 })` Updates the `B.attr` by adding the new dictionary `{'b' : 2 }`.
|
Python: Use one list to search another list and pull corresponding rows
Question: I am stuck. I have a list of strings, and I want to search through a bigger
list that has additional columns associated with those strings, and put the
strings from my first list into a new file with their associated values from
the second list (ie. take the whole row where there is a string match).
This is what I have so far
from sys import argv
script, filename, filename2, outputfile = argv
import csv #program to help manipulate csv files
with open(filename,'rU') as fin1, open(filename2, 'rU') as fin2, open (outputfile,'w') as fout: #simplifies opening and closing a file into one line
for row in fin1:
gene = row[0]
writer = csv.writer(fout, delimiter=',') #dialect must be specified, csv file so it is a ,
for gene in csv.reader(fin1, delimiter=','):
for row in csv.reader(fin2, delimiter=','):
if gene == row[4]:
writer.writerow(row)
break
Thank you
Answer:
from sys import argv
script, filename, filename2, outputfile = argv
import csv # program to help manipulate csv files with open(filename,'rU') as fin1, open(outputfile,'w') as fout: # simplifies opening and closing a file into one line
writer = csv.writer(fout, delimiter=',') # dialect must be specified, csv file so it is a ,
for row_fin1 in csv.reader(fin1, delimiter=','):
gene = row_fin1[0]
with open(filename2, 'rU') as fin2:
for row_fin2 in csv.reader(fin2, delimiter=','):
if gene == row_fin2[4]:
writer.writerow(row_fin2)
break
You need to open and close the fin2 each time, because csv reader reads only
in forward direction and cant go back. Hope this helps.
|
Python: adding value from list of lists
Question: below is my list of lists;
db_rows = [('a','b','c',4),
('a','s','f',6),
('a','c','d',6),
('a','b','f',2),
('a','b','c',6),
('a','b','f',8),
('a','s','f',6),
('a','b','f',7),
('a','s','f',5),
('a','b','f',2)]
if first three values are same in the inner list then I need to add 4th value
to create new list
I need result list like this:
final_list = [('a','b','c',10),
('a','s','f',17),
('a','c','d',6),
('a','b','f',19)]
I have tried the below script (not working):
final_list = []
for row in db_rows:
temp_flag=False
temp_list = []
val = 0
for ref_row in db_rows:
if row != ref_row:
if row[0]==ref_row[0] and row[1]==ref_row[1] and row[2]==ref_row[2]:
val = val + ref_row[3]
temp_flag=True
temp_list=(row[0],row[1],row[2],val)
if temp_flag==False:
temp_list=row
final_list.append(temp_list)
please advice me.
Answer: Use a dictionary as Dov Grobgeld commented, then convert the dictionary back
to the list.
from collections import defaultdict
db_rows = [('a','b','c',4),
('a','s','f',6),
('a','c','d',6),
('a','b','f',2),
('a','b','c',6),
('a','b','f',8),
('a','s','f',6),
('a','b','f',7),
('a','s','f',5),
('a','b','f',2)]
sums = defaultdict(int)
for row in db_rows:
sums[row[:3]] += row[3]
final_list = [key + (value,) for key, value in sums.iteritems()]
Printing `final_list` outputs:
[('a', 'b', 'c', 10), ('a', 's', 'f', 17), ('a', 'b', 'f', 19), ('a', 'c', 'd', 6)]
See
[`collections.defaultdict`](https://docs.python.org/2/library/collections.html#collections.defaultdict).
|
Python finding bolded text in RTF
Question: I'm dealing with a gigantic rich text file where every entry starts with a
bold title. It'd be really helpful to import the rich text file into Python
and have it split up lines wherever it sees bold text. However, I can't find a
way to import non plaintext, and have resorted to looking for other methods of
finding where the bold text starts.
Is there a way to get Python to read where bold text is?
Answer: No, not easily. Certainly not within the scope of a StackOverflow answer.
The problem is that RTF is a proprietary format, with special "syntax" that
describes the format.
There are libraries that make attempts to read it, which are described here:
[Is there a Python module for converting RTF to plain
text?](http://stackoverflow.com/questions/1337446/is-there-a-python-module-
for-converting-rtf-to-plain-text)
However, even if one of those would read the text for you, it would be
unlikely to be telling you the format. Afterall, how would it tell you?
Your best bet may be finding an RTF to HTML converter (at least one is
referred to in the question that I pointed to), then using BeautifulSoup to
find the bolded HTML elements.
|
Detect if specific Python.app instance is already running
Question: I am experimenting with OS X apps written in Python and need to detect if
there is already an instance of Python.app running with certain script. The
script modifies `CFBundleName` on-the-fly from `Python` to `MyApp` to change
the app title in the menubar.
bundle = NSBundle.mainBundle()
info = bundle.localizedInfoDictionary() or bundle.infoDictionary()
info['CFBundleName'] = 'MyApp'
If I start another instance and check `CFBundleName` of the running apps, it
will only tell me the original value, i.e. `Python`:
for app in NSWorkspace.sharedWorkspace().runningApplications():
bundle = NSBundle.bundleWithURL_(app.bundleURL())
info = bundle.localizedInfoDictionary() or bundle.infoDictionary()
name = info.get('CFBundleName')
if name in ('Python', 'MyApp'):
print name # => prints Python
So I need to find a way to mark a Python.app instance that runs MyApp script
to be able to abort launching duplicate instances.
Is there such way?
**Update:**
Until there is a better solution, I'll be using `lockf`
import fcntl
lockfile = open('/tmp/myapp.lock', 'w')
fcntl.lockf(lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
**Update 2:**
Well, I still need to find my application to focus. Currently, I just loop
through all Python.app instances and focus them one by one. Normally, there is
just one, but if there are few of them it can be messy.
from Foundation import NSWorkspace
from Cocoa import NSApplicationActivateAllWindows, NSApplicationActivateIgnoringOtherApps
try:
import fcntl
lockfile = open('/tmp/myapp.lock', 'w')
fcntl.lockf(lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
except IOError as e:
assert (e.errno, e.strerror) == (35, 'Resource temporarily unavailable')
for app in NSWorkspace.sharedWorkspace().runningApplications():
if app.bundleIdentifier() == 'org.python.python':
app.activateWithOptions_(NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)
exit()
**Update 3:**
I am going to use a pid file until a better solution comes up
LOCK_FILE = '/tmp/myapp.lock'
PID_FILE = '/tmp/myapp.pid'
try:
import fcntl
# NOTE: needs to be assigned to a variable for the lock to be preserved
lockfile = open(LOCK_FILE, 'w')
fcntl.lockf(lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
except IOError as e:
try:
with open(PID_FILE) as f:
pid = int(f.read())
except:
pid = None
for app in NSWorkspace.sharedWorkspace().runningApplications():
if app.bundleIdentifier() == 'org.python.python':
if not pid or pid == app.processIdentifier():
app.activateWithOptions_(NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)
exit()
from Foundation import NSProcessInfo
info = NSProcessInfo.processInfo()
pid = info.processIdentifier()
with open(PID_FILE, 'w+') as f:
f.write(str(pid))
Answer: There are several ways to solve this. Among them:
* libunique - a library specifically designed for this
* dbus - internal communications system
Many of them are described in the answers of [this
post](http://stackoverflow.com/questions/2261997/how-can-i-detect-what-other-
copy-of-python-script-is-already-running).
A recipe for unique instances is given
[here](http://code.activestate.com/recipes/474070/).
|
How to write data to stdin of the first process in a Python shell pipeline?
Question: I see this code snippet referenced quite a lot during discussions around
Python subprocess pipelines. Obligatory link:
<https://docs.python.org/3.4/library/subprocess.html#replacing-shell-pipeline>
Modified slightly:
p1 = subprocess.Popen(['cat'],
stdin=subprocess.PIPE,
stdout=subprocess.PIPE)
p2 = subprocess.Popen(['head', '-n', '1'],
stdin=p1.stdout,
stdout=subprocess.PIPE)
# Allow p1 to receive a SIGPIPE if p2 exits.
p1.stdout.close()
output = p2.communicate()[0]
This shell pipeline is pointless, except to succinctly demonstrate the
challenge. Input `"abc\ndef\nghi\n"` and only `"abc\n"` should be captured in
`output`.
What is the best way to write data to `p1.stdin`? I am aware of the `input`
argument to `subprocess.Popen.communicate()`, but it won't work in a pipeline.
Also, the solution needs to handling blocking correctly.
My guess: Reverse engineer the code behind `communicate()` and create another
version for this specific issue. Before I do that, I want to ask if there is a
simpler solution of which I am not aware.
Answer: Write to `p1.stdin` and then close it before calling `p2.communicate()`:
In [1]: import subprocess
In [2]: %cpaste
Pasting code; enter '--' alone on the line to stop or use Ctrl-D.
:p1 = subprocess.Popen(['cat'],
: stdin=subprocess.PIPE,
: stdout=subprocess.PIPE)
:p2 = subprocess.Popen(['head', '-n', '1'],
: stdin=p1.stdout,
: stdout=subprocess.PIPE)
:p1.stdout.close()
:--
In [3]: p1.stdin.write(b'This is the first line.\n')
Out[3]: 24
In [4]: p1.stdin.write(b'And here is the second line.\n')
Out[4]: 29
In [5]: p1.stdin.close()
In [6]: p2.communicate()
Out[6]: (b'This is the first line.\n', None)
(Don't forget the newlines in the data you send to `cat`, or it won't work.)
|
Python decorate methods with variable number of positional args and optional arg
Question: I am writing my first Python (3.4) application using SQLalchemy. I have
several methods which all have a very similar pattern. They take an optional
argument `session` which defaults to `None`. If `session` is passed, the
function uses that session, otherwise it opens and uses a new session. For
example, consider the following method:
def _stocks(self, session=None):
"""Return a list of all stocks in database."""
newsession = False
if not session:
newsession = True
session = self.db.Session()
stocks = [stock.ticker for stock in session.query(Stock).all()]
if newsession:
session.close()
return stocks
So, being new to Python and eager to learn all of its power, I thought this
smelt like the perfect time to learn a little something about Python
decorators. So after a lot of reading, like this [this series of blog
posts](http://www.artima.com/weblogs/viewpost.jsp?thread=240808) and
[this](http://stackoverflow.com/a/1594484/4530863) fantastic SO answer, I
wrote the following decorator:
from functools import wraps
def session_manager(func):
"""
Manage creation of session for given function.
If a session is passed to the decorated function, it is simply
passed through, otherwise a new session is created. Finally after
execution of decorated function, the new session (if created) is
closed/
"""
@wraps(func)
def inner(that, session=None, *args, **kwargs):
newsession = False
if not session:
newsession = True
session = that.db.Session()
func(that, session, *args, **kwargs)
if newsession:
session.close()
return func(that, session, *args, **kwargs)
return inner
And it seems to work great. The original method is now reduced to:
@session_manager
def _stocks(self, session=None):
"""Return a list of all stocks in database."""
return [stock.ticker for stock in session.query(Stock).all()]
HOWEVER, when I apply the decorator to a function that takes some positional
arguments in addition to the optional `session`, I get an error. So trying to
write:
@session_manager
def stock_exists(self, ticker, session=None):
"""
Check for existence of stock in database.
Args:
ticker (str): Ticker symbol for a given company's stock.
session (obj, optional): Database session to use. If not
provided, opens, uses and closes a new session.
Returns:
bool: True if stock is in database, False otherwise.
"""
return bool(session.query(Stock)
.filter_by(ticker=ticker)
.count()
)
and running like `print(client.manager.stock_exists('AAPL'))` gives an
`AttributeError` with the following traceback:
Traceback (most recent call last):
File "C:\Code\development\Pynance\pynance.py", line 33, in <module>
print(client.manager.stock_exists('GPX'))
File "C:\Code\development\Pynance\pynance\decorators.py", line 24, in inner
func(that, session, *args, **kwargs)
File "C:\Code\development\Pynance\pynance\database\database.py", line 186, in stock_exists
.count()
AttributeError: 'NoneType' object has no attribute 'query'
[Finished in 0.7s]
So I am guessing by the traceback, that I am messing up the order of the
arguments, but I can't figure out how to order them properly. I have functions
that I want to decorate that can take 0-3 arguments in addition to the
`session`. Can someone please point out the error in my methodology?
Answer: Change
def inner(that, session=None, *args, **kwargs):
to
def inner(that, *args, session=None, **kwargs):
and
return func(that, session, *args, **kwargs)
to
return func(that, *args, session=session, **kwargs)
It works:
def session_manager(func):
def inner(that, *args, session=None, **kwargs):
if not session:
session = object()
return func(that, *args, session=session, **kwargs)
return inner
class A():
@session_manager
def _stocks(self, session=None):
print(session)
return True
@session_manager
def stock_exists(self, ticker, session=None):
print(ticker, session)
return True
a = A()
a._stocks()
a.stock_exists('ticker')
Output:
$ python3 test.py
<object object at 0x7f4197810070>
ticker <object object at 0x7f4197810070>
When you use `def inner(that, session=None, *args, **kwargs)` any second
positional argument (counting `self`) is treated as `session` argument. So
when you call `manager.stock_exists('AAPL')` `session` gets value `AAPL`.
|
sklearn: Using CountVectorizer object to get a feature vector of a new string
Question: So I create a CountVectorizer object by executing following lines.
count_vectorizer = CountVectorizer(binary='true')
data = count_vectorizer.fit_transform(data)
Now I have a new string and I would want to map this string to the TDM matrix
that i get from CountVectorizer. So what I am expecting for a string I input
to the TDM, is a corresponding document term vector.
I tried,
count_vectorizer.transform([string])
Gave an error, AttributeError: transform not found Adding a a part of the
stacktrace, Its a long stacktrace and hence I am adding just the relevant bits
which are the last few lines of the trace.
File "/Users/ankit/Desktop/geny/APIServer/RUNTIME/src/controller/sentiment/Sentiment.py", line 29, in computeSentiment
vec = self.models[model_name]["vectorizer"].transform([string])
File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/scipy/sparse/base.py", line 440, in __getattr__
raise AttributeError(attr + " not found")
Please advice.
Thanks
Ankit S
Answer: The example you showed wasn't reproducible - what is the string variable here?
However following code seems to work perfectly:-
from sklearn.feature_extraction.text import CountVectorizer
data = ["aa bb cc", "cc dd ee"]
count_vectorizer = CountVectorizer(binary='true')
data = count_vectorizer.fit_transform(data)
# Check if your vocabulary is being built perfectly
print count_vectorizer.vocabulary_
# Trying a couple new string with added new word. new word should be ignored
newData = count_vectorizer.transform(["aa dd mm", "aa bb"])
print newData
# You can get the array by writing
print newData.toarray()
Well, count_vectorizer.transform() accepts list of strings - not a single
string. If the transform-fitting didn't work, it should have raised
"ValueError: Vocabulary wasn't fitted or is empty!" In case of errors of this
kind, paste the whole traceback stack (exception stack). No one can see where
AttributeError is coming from - your code or some internal bug in sklearn.
|
(Python Unicurses) stdscr not passing between files?
Question: I've been trying to learn Curses (Unicurses since I'm on Windows) and have
been following a tutorial, but I've gotten stuck. I am running into this error
message:
D:\Python34>python ./project/cursed.py
Traceback (most recent call last):
File "./project/cursed.py", line 35, in <module>
main()
File "./project/cursed.py", line 20, in main
obj_player = Player(stdscr, "@")
File "D:\Python34\project\cursedplayer.py", line 10, in __init__
self.max_x = stdscr.getmaxyx()[1] - 1
AttributeError: 'c_void_p' object has no attribute 'getmaxyx'
What I can glean from that is something is going wrong when trying to get the
stdscr variable between the two files. Here is the file that has the function
I'm trying to call:
from unicurses import *
from cursedfunction import *
class Player:
def __init__(self, stdscr, body, fg = None, bg = None, attr = None):
self.max_x = stdscr.getmaxyx()[1] - 1
self.max_y = stdscr.getmaxyx()[0] - 1
self.x = self.max_x / 2
self.y = self.max_y / 2
self.body = body
del stdscr
#create player
self.window = newwin(1, 1, self.y, self.x)
waddstr(self.window, self.body)
self.panel = new_panel(self.window)
self.fg = fg
self.bg = bg
self.color = 0
self.attr = attr
if (fg != None) and (bg != None):
self.set_colors(fg, bg)
self.show_changes()
def set_colors(self, fg, bg):
self.color = make_color(fg, bg)
self.fg = fg
self.bg = bg
waddstr( self.window, self.body, color_pair(self.color) + self.attr)
self.show_changes()
def show_changes(self):
update_panels()
doupdate()
Here is the main file that's calling the function defined in cursedplayer.py:
from unicurses import *
from cursedfunction import *
from cursedplayer import *
#lines is 80
#columns is 25
def main():
stdscr = initscr()
if not has_colors():
print("You need colors to run!")
return 0
start_color()
noecho()
curs_set(False)
keypad(stdscr, True)
obj_player = Player(stdscr, "@")
update_panels()
doupdate()
running = True
while running:
key = getch()
if key == 27:
running = False
break
endwin()
if (__name__ == "__main__"):
main()
I'd appreciate any help. I've been searching around but haven't found anything
relevant to my problem. I can't proceed with the curses tutorial I'm following
because of this error. Thank you for reading.
(cursedfunction.py isn't included because it doesn't have any relevant info,
just a function that makes colors)
Answer: Ah! I am very dumb. The error message was giving me all the info I need --
specifically, that stdscr didn't have a function called 'getmaxyx'. I was
inputting the command wrong!
Going from this:
self.max_x = stdscr.getmaxyx()[1] - 1
self.max_y = stdscr.getmaxyx()[0] - 1
To this:
self.max_x = getmaxyx(stdscr)[1] - 1
self.max_y = getmaxyx(stdscr)[0] - 1
...was able to pass the information in a format that I needed. Why it worked
in the tutorial I don't know, but I blame black magic.
|
Create table in mysqldb
Question:
Traceback (most recent call last):
File "****", line 17, in module
cur.execute("CREATE TABLE `Project1`(`Id` INT PRIMARY KEY NOT NULL ,`TERM` VARCHAR(25) CHARACTER SET utf8 NOT NULL, `TYPE1` VARCHAR(25) CHARACTER SET utf8 NOT NULL, `ACTION` VARCHAR(30) CHARACTER SET utf8 NOT NULL, `CERTAINITY` DOUBLE(3) NOT NULL");
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 205, in execute
self.errorhandler(self, exc, value)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
_mysql_exceptions.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') NOT NULL' at line 1")
line 1: import mysqldb as mdb
after rectifying the double problem, I got a similar error, with the last
sentence changed as _mysql_exceptions.ProgrammingError: (1064, "You have an
error in your SQL syntax; check the manual that corresponds to your MySQL
server version for the right syntax to use near '' at line 1")
the line to create tables was modified to CREATE TABLE `Project1`(`Id` INT
PRIMARY KEY NOT NULL ,`Term` VARCHAR(25) CHARACTER SET utf8 NOT NULL, `Type1`
VARCHAR(25) CHARACTER SET utf8 NOT NULL, `Action` VARCHAR(30) CHARACTER SET
utf8 NOT NULL, `Certainity` DOUBLE(4,3) NOT NULL)
NEW PROBLEM,
I changed 'Certainity' to string
File "/home/ankitaprasad/Ontology Project3/Stanford.py", line 57, in <module>
cur.execute("""INSERT INT0 Project1(Term, Type1, Action, Certainity) VALUES (%s,%s,%s,%s)""",(term,type1,action,ab));
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 205, in execute
self.errorhandler(self, exc, value)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
_mysql_exceptions.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Project1(Term, Type1, Action, Certainity) VALUES ('','','','0')' at line 1")
[Finished in 1.2s with exit code 1]
here ab=str(mod)
Answer: First off, your entire create statement formatted into this:
CREATE TABLE `Project1` (
`Id` INT PRIMARY KEY NOT NULL,
`TERM` VARCHAR(25) CHARACTER SET utf8 NOT NULL,
`TYPE1` VARCHAR(25) CHARACTER SET utf8 NOT NULL,
`ACTION` VARCHAR(30) CHARACTER SET utf8 NOT NULL,
`CERTAINITY` DOUBLE(3) NOT NULL
See where you are missing the closing parentheses? Fixing that, you still have
a problem as [`DOUBLE`](https://dev.mysql.com/doc/refman/5.5/en/floating-
point-types.html) require _two_ arguments, not one, so that is a syntax error
for MySQL. Please read the documentation and carefully look at what you wrote
before asking questions and it will save you a lot of time, especially shortly
before a deadline.
|
NoReverseMatch at /resetpassword/ in Django
Question: I´m getting this error during Reset Password. I have a login page whith the
link to reset forgotten password, it shows correctly the templates, but if I
write the mail to send the reset link, it shows this error:
**localhost/resesetpassword**
NoReverseMatch at /resetpassword/
Reverse for 'password_reset_confirm' with arguments '()' and keyword arguments '{'token': '42e-71994a9bf9d36c22eb95', 'uidb64': b'MQ'}' not found. 0 pattern(s) tried: []
Request Method: POST
Request URL: http://localhost/resetpassword/
Django Version: 1.8.2
Exception Type: NoReverseMatch
Exception Value:
Reverse for 'password_reset_confirm' with arguments '()' and keyword arguments '{'token': '42e-71994a9bf9d36c22eb95', 'uidb64': b'MQ'}' not found. 0 pattern(s) tried: []
Exception Location: C:\Python34\lib\site- packages\django\core\urlresolvers.py in _reverse_with_prefix, line 496
Python Executable: C:\Python34\python.exe
Python Version: 3.4.3
Python Path:
['c:\\labsoft',
'C:\\Python34\\lib\\site-packages\\psycopg2-2.6-py3.4-win-amd64.egg',
'C:\\Windows\\SYSTEM32\\python34.zip',
'C:\\Python34\\DLLs',
'C:\\Python34\\lib',
'C:\\Python34',
'C:\\Python34\\lib\\site-packages']
Server time: Dom, 7 Jun 2015 21:46:55 -0500
**Error during template rendering**
In template C:\Python34\lib\site- packages\django\contrib\admin\templates\registration\password_reset_email.html, error at line 6
1 {% load i18n %}{% autoescape off %}
2 {% blocktrans %}You're receiving this email because you requested a password reset for your user account at {{ site_name }}.{% endblocktrans %}
3
4 {% trans "Please go to the following page and choose a new password:" %}
5 {% block reset_link %}
6
{{ protocol }}://{{ domain }}
{% url 'password_reset_confirm' uidb64=uid token=token %}
7 {% endblock %}
8 {% trans "Your username, in case you've forgotten:" %} {{ user.get_username }}
9
10 {% trans "Thanks for using our site!" %}
11
12 {% blocktrans %}The {{ site_name }} team{% endblocktrans %}
13
14 {% endautoescape %}
15
**It shows this code in red:**
{{ protocol }}://{{ domain }}
{% url 'password_reset_confirm' uidb64=uid token=token %}
**I think the error can be the protocol and domain parameters, but I don't
know how fix it. Thanks a lot!!!**
**urls.py**
from django.conf.urls import patterns, url
from .views import Buscar_view
urlpatterns = patterns('melomanos.views',
url(r'^$','trabajos_all_view',name='url_index'),
url(r'^register/$','register_view',name='vista_registro'),
url(r'^login/$','login_view',name='vista_login'),
url(r'^logout/$','logout_view',name='vista_logout'),
url(r'^perfil/$','registro_view',name='vista_perfil'),
url(r'^publicar/$','trabajomusical_view', name='vista_publicar'),
url(r'^trabajos/$','trabajos_view',name='vista_trabajos'),
url(r'^trabajo/(?P<id_trabajo>.*)/$','solo_trabajo_view', name='vista_trabajo'),
url(r'^buscar/$',Buscar_view.as_view(),name='vista_buscar'),
)
urlpatterns += patterns('',
url(r'^resetpassword/passwordsent/$', 'django.contrib.auth.views.password_reset_done', name='password_reset_done'),
url(r'^resetpassword/$', 'django.contrib.auth.views.password_reset', name="reset_password"),
url(r'^reset/(?P<uidb64>[0-9A-Za-z]+)-(?P<token>,+)/$', 'django.contrib.auth.views.password_reset_confirm'),
url(r'^reset/done/$', 'django.contrib.auth.views.password_reset_complete',{'template_name' : 'registration/password_reset.html', 'post_reset_redirect': '/logout/' }),
)
Answer: Actually your regex for the token parameter is matching a single or multiples
commas.
You can use `<token>.+` for match any character.
Also your pattern is looking for a `-` between the `uidb64` and `token`, and
this line
{% url 'password_reset_confirm' uidb64=uid token=token %}
is passing both parameters without the `-`.
You need just to alter the url line as folow:
url(r'^reset/(?P<uidb64>[0-9A-Za-z]+)/(?P<token>.+)/$', 'django.contrib.auth.views.password_reset_confirm', name='password_reset_confirm'),
|
Elements arrangement in Python
Question: Every element of the array "data" have to be changed as follows:
For example, 4 should be seen in names_A and data_A. The names_A for 4 is
'David'. Now 'David' should be seen in names_B and data_B. The data_B for
'David' is 30. So, the element 4 must be changed by 30; and so on.
import numpy as np
names_A = ['David', 'Mark', 'Brian', 'Michael']
data_A = [4,3,1,2]
names_B = ['Mark', 'David', 'Michael', 'Brian']
data_B = [51,30,11,29]
data = np.array([[4,4,3,3,2,2,1,1,3,3],
[4,3,3,3,2,2,3,1,3,1],
[4,2,3,3,2,2,4,1,4,3]])
How is the easiest and simplest way of doing it?
I tried it as follows:
dats = data.ravel()
results = []
for d in dats:
nam_A = names_A[data_A == int(d)]
dat_B = data_B[names_B == nam_A]
results.append(dat_B)
print np.array(results).reshape(data.shape)
[[51 51 51 51 51 51 51 51 51 51]
[51 51 51 51 51 51 51 51 51 51]
[51 51 51 51 51 51 51 51 51 51]]
But, it's giving wrong results. How would you do it?
Answer: Use dictionaries to create a mapping.
names_A = ['David', 'Mark', 'Brian', 'Michael']
data_A = [4,3,1,2]
names_B = ['Mark', 'David', 'Michael', 'Brian']
data_B = [51,30,11,29]
lookup_a = dict(zip(names_A, data_A))
lookup_b = dict(zip(names_B, data_B))
mapping = {value_a: lookup_b[key_a] for key_a, value_a in lookup_a.items()}
Now the keys in `mapping` will be the numbers from `data_A` with the
corresponding values from `data_B`.
I never worked with `numpy` but it looks like an easy task to do the
replacement now.
* * *
Just to give an example with a simple list:
data = [4, 4, 3, 3, 2, 2, 1, 1, 3, 3]
data = [mapping[value] for value in data]
`data` now is `[30, 30, 51, 51, 11, 11, 29, 29, 51, 51]`.
* * *
_Edited after installing numpy_
If you created the mapping dictionary you can do the following:
data = np.array([[4, 4, 3, 3, 2, 2, 1, 1, 3, 3],
[4, 3, 3, 3, 2, 2, 3, 1, 3, 1],
[4, 2, 3, 3, 2, 2, 4, 1, 4, 3]])
for row in data:
for index, value in enumerate(row):
row[index] = mapping[value]
`data` is now:
[[32 30 51 51 11 11 29 29 51 51]
[30 51 51 51 11 11 51 29 51 29]
[30 11 51 51 11 11 30 29 30 51]]
As I never worked with numpy before there might be easier (or more pythonic)
solutions, but at least this does what it should do.
|
I can't install kivy on python
Question: I want to install kivy to python. To do this I type this command:
pip install -I Cython==0.21.2
It worked. But, when I type this command:
pip install kivy
I get this error:
opengl.obj : error LNK2019: unresolved external symbol ___glewGenerateMipmap
referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewGetFramebuffer
AttachmentParameteriv referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewFramebufferRen
derbuffer referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewFramebufferTex
ture3D referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewFramebufferTex
ture2D referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewFramebufferTex
ture1D referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewCheckFramebuff
erStatus referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewDeleteFramebuf
fers referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewBindFramebuffe
r referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewIsFramebuffer
referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewGetRenderbuffe
rParameteriv referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewRenderbufferSt
orage referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewGenRenderbuffe
rs referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewDeleteRenderbu
ffers referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewBindRenderbuff
er referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewIsRenderbuffer
referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewGenFramebuffer
s referenced in function _glew_dynamic_binding
opengl.obj : error LNK2019: unresolved external symbol ___glewActiveTexture
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_glActiveTexture
opengl.obj : error LNK2019: unresolved external symbol ___glewAttachShader r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_2glAttachShader
opengl.obj : error LNK2019: unresolved external symbol ___glewBindBuffer ref
erenced in function ___pyx_pf_4kivy_8graphics_6opengl_6glBindBuffer
opengl.obj : error LNK2019: unresolved external symbol ___glewBlendColor ref
erenced in function ___pyx_pf_4kivy_8graphics_6opengl_14glBlendColor
opengl.obj : error LNK2019: unresolved external symbol ___glewBlendEquation
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_16glBlendEquation
opengl.obj : error LNK2019: unresolved external symbol ___glewBlendEquationS
eparate referenced in function ___pyx_pf_4kivy_8graphics_6opengl_18glBlendEquati
onSeparate
opengl.obj : error LNK2019: unresolved external symbol ___glewBlendFuncSepar
ate referenced in function ___pyx_pf_4kivy_8graphics_6opengl_22glBlendFuncSepara
te
opengl.obj : error LNK2019: unresolved external symbol ___glewCompileShader
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_38glCompileShader
opengl.obj : error LNK2019: unresolved external symbol ___glewDeleteProgram
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_58glDeleteProgram
opengl.obj : error LNK2019: unresolved external symbol ___glewDeleteShader r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_62glDeleteShader
opengl.obj : error LNK2019: unresolved external symbol ___glewDetachShader r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_70glDetachShader
opengl.obj : error LNK2019: unresolved external symbol ___glewDisableVertexA
ttribArray referenced in function ___pyx_pf_4kivy_8graphics_6opengl_74glDisableV
ertexAttribArray
opengl.obj : error LNK2019: unresolved external symbol ___glewEnableVertexAt
tribArray referenced in function ___pyx_pf_4kivy_8graphics_6opengl_82glEnableVer
texAttribArray
opengl.obj : error LNK2019: unresolved external symbol ___glewLinkProgram re
ferenced in function ___pyx_pf_4kivy_8graphics_6opengl_174glLinkProgram
opengl.obj : error LNK2019: unresolved external symbol ___glewSampleCoverage
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_186glSampleCoverage
opengl.obj : error LNK2019: unresolved external symbol ___glewStencilFuncSep
arate referenced in function ___pyx_pf_4kivy_8graphics_6opengl_196glStencilFuncS
eparate
opengl.obj : error LNK2019: unresolved external symbol ___glewStencilMaskSep
arate referenced in function ___pyx_pf_4kivy_8graphics_6opengl_200glStencilMaskS
eparate
opengl.obj : error LNK2019: unresolved external symbol ___glewStencilOpSepar
ate referenced in function ___pyx_pf_4kivy_8graphics_6opengl_204glStencilOpSepar
ate
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform1f refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_218glUniform1f
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform1i refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_222glUniform1i
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform2f refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_226glUniform2f
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform2i refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_230glUniform2i
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform3f refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_234glUniform3f
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform3i refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_238glUniform3i
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform4f refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_242glUniform4f
opengl.obj : error LNK2019: unresolved external symbol ___glewUniform4i refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_246glUniform4i
opengl.obj : error LNK2019: unresolved external symbol ___glewUseProgram ref
erenced in function ___pyx_pf_4kivy_8graphics_6opengl_256glUseProgram
opengl.obj : error LNK2019: unresolved external symbol ___glewValidateProgra
m referenced in function ___pyx_pf_4kivy_8graphics_6opengl_258glValidateProgram
opengl.obj : error LNK2019: unresolved external symbol ___glewVertexAttrib1f
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_260glVertexAttrib1f
opengl.obj : error LNK2019: unresolved external symbol ___glewVertexAttrib2f
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_264glVertexAttrib2f
opengl.obj : error LNK2019: unresolved external symbol ___glewVertexAttrib3f
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_268glVertexAttrib3f
opengl.obj : error LNK2019: unresolved external symbol ___glewVertexAttrib4f
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_272glVertexAttrib4f
opengl.obj : error LNK2019: unresolved external symbol ___glewCreateProgram
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_48glCreateProgram
opengl.obj : error LNK2019: unresolved external symbol ___glewCreateShader r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_50glCreateShader
opengl.obj : error LNK2019: unresolved external symbol ___glewGenBuffers ref
erenced in function ___pyx_pf_4kivy_8graphics_6opengl_94glGenBuffers
opengl.obj : error LNK2019: unresolved external symbol ___glewGetActiveAttri
b referenced in function ___pyx_pf_4kivy_8graphics_6opengl_104glGetActiveAttrib
opengl.obj : error LNK2019: unresolved external symbol ___glewGetActiveUnifo
rm referenced in function ___pyx_pf_4kivy_8graphics_6opengl_106glGetActiveUnifor
m
opengl.obj : error LNK2019: unresolved external symbol ___glewGetAttachedSha
ders referenced in function ___pyx_pf_4kivy_8graphics_6opengl_108glGetAttachedSh
aders
opengl.obj : error LNK2019: unresolved external symbol ___glewGetProgramiv r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_124glGetProgramiv
opengl.obj : error LNK2019: unresolved external symbol ___glewGetProgramInfo
Log referenced in function ___pyx_pf_4kivy_8graphics_6opengl_126glGetProgramInfo
Log
opengl.obj : error LNK2019: unresolved external symbol ___glewGetShaderiv re
ferenced in function ___pyx_pf_4kivy_8graphics_6opengl_130glGetShaderiv
opengl.obj : error LNK2019: unresolved external symbol ___glewGetShaderInfoL
og referenced in function ___pyx_pf_4kivy_8graphics_6opengl_132glGetShaderInfoLo
g
opengl.obj : error LNK2019: unresolved external symbol ___glewGetShaderSourc
e referenced in function ___pyx_pf_4kivy_8graphics_6opengl_136glGetShaderSource
opengl.obj : error LNK2019: unresolved external symbol ___glewGetUniformfv r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_144glGetUniformfv
opengl.obj : error LNK2019: unresolved external symbol ___glewGetUniformiv r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_146glGetUniformiv
opengl.obj : error LNK2019: unresolved external symbol ___glewGetVertexAttri
bfv referenced in function ___pyx_pf_4kivy_8graphics_6opengl_150glGetVertexAttri
bfv
opengl.obj : error LNK2019: unresolved external symbol ___glewGetVertexAttri
biv referenced in function ___pyx_pf_4kivy_8graphics_6opengl_152glGetVertexAttri
biv
opengl.obj : error LNK2019: unresolved external symbol ___glewIsBuffer refer
enced in function ___pyx_pf_4kivy_8graphics_6opengl_158glIsBuffer
opengl.obj : error LNK2019: unresolved external symbol ___glewIsProgram refe
renced in function ___pyx_pf_4kivy_8graphics_6opengl_164glIsProgram
opengl.obj : error LNK2019: unresolved external symbol ___glewIsShader refer
enced in function ___pyx_pf_4kivy_8graphics_6opengl_168glIsShader
opengl.obj : error LNK2019: unresolved external symbol ___glewBindAttribLoca
tion referenced in function ___pyx_pf_4kivy_8graphics_6opengl_4glBindAttribLocat
ion
opengl.obj : error LNK2019: unresolved external symbol ___glewBufferData ref
erenced in function ___pyx_pf_4kivy_8graphics_6opengl_24glBufferData
opengl.obj : error LNK2019: unresolved external symbol ___glewBufferSubData
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_26glBufferSubData
opengl.obj : error LNK2019: unresolved external symbol ___glewCompressedTexI
mage2D referenced in function ___pyx_pf_4kivy_8graphics_6opengl_40glCompressedTe
xImage2D
opengl.obj : error LNK2019: unresolved external symbol ___glewCompressedTexS
ubImage2D referenced in function ___pyx_pf_4kivy_8graphics_6opengl_42glCompresse
dTexSubImage2D
opengl.obj : error LNK2019: unresolved external symbol ___glewDeleteBuffers
referenced in function ___pyx_pf_4kivy_8graphics_6opengl_54glDeleteBuffers
opengl.obj : error LNK2019: unresolved external symbol ___glewGetAttribLocat
ion referenced in function ___pyx_pf_4kivy_8graphics_6opengl_110glGetAttribLocat
ion
opengl.obj : error LNK2019: unresolved external symbol ___glewGetBufferParam
eteriv referenced in function ___pyx_pf_4kivy_8graphics_6opengl_114glGetBufferPa
rameteriv
opengl.obj : error LNK2019: unresolved external symbol ___glewGetUniformLoca
tion referenced in function ___pyx_pf_4kivy_8graphics_6opengl_148glGetUniformLoc
ation
opengl.obj : error LNK2019: unresolved external symbol ___glewShaderSource r
eferenced in function ___pyx_pf_4kivy_8graphics_6opengl_192glShaderSource
opengl.obj : error LNK2019: unresolved external symbol ___glewUniformMatrix4
fv referenced in function ___pyx_pf_4kivy_8graphics_6opengl_254glUniformMatrix4f
v
opengl.obj : error LNK2019: unresolved external symbol ___glewVertexAttribPo
inter referenced in function ___pyx_pf_4kivy_8graphics_6opengl_276glVertexAttrib
Pointer
build\lib.win32-2.7\kivy\graphics\opengl.pyd : fatal error LNK1120: 79 unres
olved externals
error: command '"C:\Users\ESES\AppData\Local\Programs\Common\Microsoft\Visu
al C++ for Python\9.0\VC\Bin\link.exe"' failed with exit status 1120
----------------------------------------
Command "C:\Python27\python.exe -c "import setuptools, tokenize;__file__='c:\\us
ers\\eses\\appdata\\local\\temp\\pip-build-1jegbu\\kivy\\setup.py';exec(compile(
getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__
, 'exec'))" install --record c:\users\eses\appdata\local\temp\pip-zzv3ab-record\
install-record.txt --single-version-externally-managed --compile" failed with er
ror code 1 in c:\users\eses\appdata\local\temp\pip-build-1jegbu\kivy
I have pygame module. And, all of the installation with pip command, I get
this error:
error: invalid command 'bdist_wheel'
----------------------------------------
Failed building wheel for kivy [or module_name]*
How can I solve them ?
Answer: You can install a prebuilt binary from the gohlke pythonlibs, just choose the
appropriate version from
[here](http://www.lfd.uci.edu/~gohlke/pythonlibs/#kivy).
|
Declaration of FigureCanvasTkAgg causes memory leak
Question: I'm having difficulty figuring out just why the declaration of
FigureCanvasTkAgg causes a memory leak, I have the following lines in my class
`__init__` method:
# pndwinBottom is a paned window of the main screen
self.__drawplotFrame = Frame(pndwinBottom, width=WIDTH, height=HEIGHT) # the frame on which we will add our canvas for drawing etc.
self.__fig = plt.figure(figsize=(16,11))
self.__drawplotCanvas = FigureCanvasTkAgg(self.__fig, master=self.__drawplotFrame)
the problem is that upon running my application , and exiting, python32.exe
remains in my process window and will clog up my computer. Commenting out
these three lines however will allow my application to exit and the process
will correctly terminate. What could these lines be doing to my application
that prevents the process from ending after the application is finished?
Thanks
_edit_
* * *
The memory leak seems to be caused by only the line `self.__fig =
plt.figure(figsize=(16, 11))` . Do I need to do some sort of deconstruction
with plt before exiting?
Answer: I'm gonna guess this is caused by the pyplot figure not being destroyed when
the Tkinter window is closed.
Like in the [embedding in tk
example](http://matplotlib.org/examples/user_interfaces/embedding_in_tk.html)
try using `Figure`:
from matplotlib.figure import Figure
self.__fig = Figure(figsize=(16,11))
example use:
import Tkinter as tk
import matplotlib
matplotlib.use('TkAgg')
from matplotlib.figure import Figure
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
class App():
def __init__(self, parent):
self.__drawplotFrame = tk.Frame(parent, width=500, height=500)
self.__drawplotFrame.pack()
self.__fig = Figure(figsize=(16,11))
self.__p = self.__fig.add_subplot(1,1,1)
self.__p.plot(range(10), range(10))
self.__drawplotCanvas = FigureCanvasTkAgg(self.__fig, master=self.__drawplotFrame)
self.__drawplotCanvas.get_tk_widget().pack(side=tk.TOP, fill=tk.BOTH, expand=1)
root = tk.Tk()
App(root)
root.mainloop()
|
local variable referenced before assignment in strange condition
Question: I have some code that takes input from an open source database, then returns a
report based on some of the tables. I could have sworn that this code was
working correctly yesterday, but when I boot it up today:
Traceback (most recent call last):
File "C:\Users\whicaso1\Downloads\eclipse-standard-luna-R-win32-x86_64\eclipse\plugins\org.python.pydev_3.6.0.201406232321\pysrc\pydevd.py", line 1845, in
debugger.run(setup['file'], None, None)
File "C:\Users\whicaso1\Downloads\eclipse-standard-luna-R-win32-x86_64\eclipse\plugins\org.python.pydev_3.6.0.201406232321\pysrc\pydevd.py", line 1373, in run
pydev_imports.execfile(file, globals, locals) # execute the script
File "C:\Users\whicaso1\workspace\Status based chilli list\CreateChiliLog.py", line 29, in
CreateChiliLog()
File "C:\Users\whicaso1\workspace\Status based chilli list\CreateChiliLog.py", line 15, in CreateChiliLog
for chili in chili_database.getChilis(status):
File "C:\Users\whicaso1\workspace\Status based chilli list\ChiliFunctions.py", line 99, in getChilis
connection_chili.rollback()
UnboundLocalError: local variable 'connection_chili' referenced before assignment
Now, I'm not a moron, I checked to see if I had, in fact, referenced the
variable "connection_chili" before assignment, but it looks like the error
occurred _while_ assigning. (here is the code snippet that failed, the error
is on the line where the connection_chili variable is being assigned to a
mysqldb database object.)
def getChilis(self, status):
try:
connection_chili = MySQLdb.connect(self.host_, self.user_, self.password_, self.database_)
cursor = connection_chili.cursor()
query = "SELECT id FROM issues WHERE status_id = %i" % status
cursor.execute(query)
connection_chili.commit()
chilis = cursor.fetchall()
cursor.close()
return chilis
except Exception, e:
connection_chili.rollback()
print "ERROR: " + str(e)
`
is there some issue with my code, or is there some weird thing going on with
my python compiler?
Answer: Just checked my code against python in cmd, and it ran fine. So I'm guessing
its probably some weird issue with eclipse. In any case, its no longer a
programming question, so I'm going to close it
|
Decorated class looses acces to its attributes
Question: I implemented a decorator that worked like a charm until I added attributes to
the decorated class. When I instantiate the class, it cannot acces the calss
attributes. Take the following minimal working example :
from module import specialfunction
class NumericalMathFunctionDecorator:
def __init__(self, enableCache=True):
self.enableCache = enableCache
def __call__(self, wrapper):
def numericalmathfunction(*args, **kwargs):
func = specialfunction(wrapper(*args, **kwargs))
"""
Do some setup to func with decorator arguments (e.g. enableCache)
"""
return numericalmathfunction
@NumericalMathFunctionDecorator(enableCache=True)
class Wrapper:
places = ['home', 'office']
configs = {
'home':
{
'attr1': 'path/at/home',
'attr2': 'jhdlt'
},
'office':
{
'attr1': 'path/at/office',
'attr2': 'sfgqs'
}
}
def __init__(self, where='home'):
# Look for setup configuration on 'Wrapper.configs[where]'.
assert where in Wrapper.places, "Only valid places are {}".format(Wrapper.places)
self.__dict__.update(Wrapper.configs[where])
def __call__(self, X):
"""Do stuff with X and return the result
"""
return X ** 2
model = Wrapper()
When I instantiate the Wrapper class (#1), I get the following error :
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-5-a99bd3d544a3> in <module>()
15 assert where in Wrapper.places, "Only valid places are {}".format(Wrapper.places)
16
---> 17 model = Wrapper()
<ipython-input-5-a99bd3d544a3> in numericalmathfunction(*args, **kwargs)
5 def __call__(self, wrapper):
6 def numericalmathfunction(*args, **kwargs):
----> 7 func = wrapper(*args, **kwargs)
8 return numericalmathfunction
9
<ipython-input-5-a99bd3d544a3> in __init__(self, where)
13 def __init__(self, where='home'):
14 # Look for setup configuration on 'Wrapper.configs[where]'.
---> 15 assert where in Wrapper.places, "Only valid places are {}".format(Wrapper.places)
16
17 model = Wrapper()
AttributeError: 'function' object has no attribute 'places'
I guess that with the decorator, Wrapper becomes a function that looses acces
to its attributes...
Any ideas of how I can solve this ? Maybe there is a workaround
Answer: You replaced `Wrapper` (which was a class) with the `numericalmathfunction`
function object. That object doesn't have any of the class attributes, no.
In essence, the decorator does this:
class Wrapper:
# ...
Wrapper = NumericalMathFunctionDecorator(enableCache=True)(Wrapper)
so whatever the `NumericalMathFunctionDecorator.__call__` method returns has
now replaced the class; all references to `Wrapper` now reference that return
value. And when you use the name `Wrapper` in the `__init__` method, you are
referencing that global, not the original class.
You can still access the current class with `type(self)`, or just reference
those attributes via `self` (where the name lookup falls through to the
class):
def __init__(self, where='home'):
# Look for setup configuration on 'Wrapper.configs[where]'.
assert where in self.places, "Only valid places are {}".format(self.places)
self.__dict__.update(self.configs[where])
or
def __init__(self, where='home'):
# Look for setup configuration on 'Wrapper.configs[where]'.
cls = type(self)
assert where in cls.places, "Only valid places are {}".format(cls.places)
self.__dict__.update(cls.configs[where])
In both cases you can end up with referencing an attribute on a subclass if
you ever did subclass `Wrapper` (which you cannot do in this case anyway as
you would have to fish the class out of the decorator closure).
Alternatively, you could store the original class as an attribute on the
returned function:
def __call__(self, wrapper):
def numericalmathfunction(*args, **kwargs):
func = specialfunction(wrapper(*args, **kwargs))
"""
Do some setup to func with decorator arguments (e.g. enableCache)
"""
numericalmathfunction.__wrapped__ = wrapper
return numericalmathfunction
then use that reference in your `__init__`:
def __init__(self, where='home'):
# Look for setup configuration on 'Wrapper.configs[where]'.
cls = Wrapper
while hasattr(cls, '__wrapped__'):
# remove any decorator layers to get to the original
cls = cls.__wrapped__
assert where in cls.places, "Only valid places are {}".format(cls.places)
self.__dict__.update(cls.configs[where])
|
TypeError: encoding or errors without a string argument
Question: I'm trying to write a list of datas to a csv file. Since the it's a list of
byte strings, I used the below code
with open(r"E:\Avinash\Python\extracting-drug-data\out.csv", "wb") as w:
writer = csv.writer(w)
writer.writerows(bytes(datas, 'UTF-8'))
But it results in the following error:
> TypeError: encoding or errors without a string argument
`datas` is a list of byte strings.
print(datas)
yields
[b'DB08873', b' MOLSDFPDBSMILESInChIView Structure \xc3\x97Structure for DB08873 (Boceprevir) Close', b'394730-60-0', b'LHHCSNFAOIFYRV-DOVBMPENSA-N', b'Organic acids and derivatives ', b'Food increases exposure of boceprevir by up to 65% relative to fasting state. However, type of food and time of meal does not affect bioavailability of boceprevir and thus can be taken without regards to food. \r\nTmax = 2 hours;\r\nTime to steady state, three times a day dosing = 1 day;\r\nCmax]
I want the above list to be printed as first row in a csv file with the
decoding of unicode chars. That is, `\xc3\x97` should be converted to it's
corresponding character.
Answer: It seems your `datas` _is_ already in bytes format, so to turn it into UTF-8
strings, you have to use `str`, not `bytes`! Also, you have to convert each
element from `datas` individually, not the entire list at once. Finally, if
you want to add `datas` as one row to `out.csv`, you have to use `writerow`,
whereas `writerows` would write _all_ the rows at once, and accordinly would
expect a list of lists.
Depending on your OS, you might also have to specify the `encoding` when
opening the file. Otherwise it will use the OS' default encoding, which might
be something entirely different.
This _seems_ to do what you want. The result is a CSV file with one row1 of
data in UTF-8 format, and the `\xc3\x97` is decoded to `×`.
import csv
with open(r"out.csv", "w", encoding='UTF-8') as w:
writer = csv.writer(w)
writer.writerow([str(d, 'UTF-8') for d in datas])
* * *
1) Note that the last item in `datas` contains some line breaks, and thus will
be split onto several lines. This is probably not what you want. Or is this a
glitch in your `datas` list?
|
Python - pull things from the bottom of the code
Question: I have this code:
import fcntl, socket, struct
import base64
import time, datetime
import netifaces
from Tkinter import *
def getHwAddr(ifname):
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
info = fcntl.ioctl(s.fileno(), 0x8927, struct.pack('256s', ifname[:15]))
return '-'.join(['%02x' % ord(char) for char in info[18:24]])
tvip = "10.0.1.2"
tvappstring = "UE55C8000"
myip = netifaces.ifaddresses(netifaces.gateways()['default'][netifaces.AF_INET][1])[netifaces.AF_INET][0]['addr']
mymac = getHwAddr(netifaces.gateways()['default'][netifaces.AF_INET][1])
appstring = "Pepin's Samsung TV Remote"
remotename = "Pepin's Samsung TV Remote"
def sendKey(skey, dataSock, appstring):
messagepart3 = chr(0x00) + chr(0x00) + chr(0x00) + chr(len(
base64.b64encode(skey))) + chr(0x00) + base64.b64encode(skey);
part3 = chr(0x00) + chr(len(appstring)) + chr(0x00) \
+ appstring + chr(len(messagepart3)) + chr(0x00) + messagepart3
dataSock.send(part3);
def sendText(stext, dataSock, appstring):
messagepart3 = chr(0x00) + chr(0x00) + chr(0x00) + chr(len(
base64.b64encode(stext))) + chr(0x00) + base64.b64encode(stext);
part3 = chr(0x00) + chr(len(appstring)) + chr(0x00) \
+ appstring + chr(len(messagepart3)) + chr(0x00) + messagepart3
dataSock.send(part3);
root = Tk()
root.title("Pepin's Samsung TV Remote")
root.geometry("391x595")
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((tvip, 55000))
ipencoded = base64.b64encode(myip)
macencoded = base64.b64encode(mymac)
messagepart1 = chr(0x64) + chr(0x00) + chr(len(ipencoded)) \
+ chr(0x00) + ipencoded + chr(len(macencoded)) + chr(0x00) \
+ macencoded + chr(len(base64.b64encode(remotename))) + chr(0x00) \
+ base64.b64encode(remotename)
part1 = chr(0x00) + chr(len(appstring)) + chr(0x00) + appstring \
+ chr(len(messagepart1)) + chr(0x00) + messagepart1
sock.send(part1)
messagepart2 = chr(0xc8) + chr(0x00)
part2 = chr(0x00) + chr(len(appstring)) + chr(0x00) + appstring \
+ chr(len(messagepart2)) + chr(0x00) + messagepart2
sock.send(part2);
class Application():
"""Pepin's Samsung TV Remote"""
def __init__(self, master):
self.master = master
self.create_widgets()
def create_widgets(self):
btn_key_poweroff = Button(self.master, text = "Power", bg="red", width=4, height=2, command = lambda: sendKey("KEY_POWEROFF", sock, tvappstring))
entry_send_custom = Entry(self.master, width=22)
entry_send_custom.grid(row=1, column=3, columnspan=4, padx=(15,0), ipady=8)
btn_send_custom = Button(self.master, text = "SEND CUSTOM KEY", width=19, height=2, command = lambda: sendText(entry_send_custom.get(), sock, tvappstring))
btn_send_custom.grid(row=2, column=3, columnspan=5, padx=(15,0))
label_tvip = Label(self.master, text="TV IP:")
label_tvip.grid(row=3, column=3, columnspan=1, padx=(15,0), ipady=8)
self.entry_tvip = Entry(self.master, width=16)
self.entry_tvip.grid(row=3, column=4, columnspan=3, ipady=8)
label_tvappstring = Label(self.master, text="TV MODEL (Tv App String)")
label_tvappstring.grid(row=4, column=3, columnspan=4, padx=(15,0), ipady=8, sticky=W)
self.entry_tvappstring = Entry(self.master, width=22)
self.entry_tvappstring.grid(row=5, column=3, columnspan=4, padx=(15,0), ipady=8)
self.entry_tvappstring.insert(0, "UE55C8000")
btn_connect = Button(self.master, text = "CONNECT TO TV", width=19, height=2, command = lambda: self.Connection())
btn_connect.grid(row=6, column=3, columnspan=5, padx=(15,0))
app = Application(root)
root.mainloop()
sock.close()
But I want to use `entry_tvip.get()` in top of the code.
Is there simple way to do it?
And start this section of the code:
sock.connect((tvip, 55000))
ipencoded = base64.b64encode(myip)
macencoded = base64.b64encode(mymac)
messagepart1 = chr(0x64) + chr(0x00) + chr(len(ipencoded)) \
+ chr(0x00) + ipencoded + chr(len(macencoded)) + chr(0x00) \
+ macencoded + chr(len(base64.b64encode(remotename))) + chr(0x00) \
+ base64.b64encode(remotename)
part1 = chr(0x00) + chr(len(appstring)) + chr(0x00) + appstring \
+ chr(len(messagepart1)) + chr(0x00) + messagepart1
sock.send(part1)
messagepart2 = chr(0xc8) + chr(0x00)
part2 = chr(0x00) + chr(len(appstring)) + chr(0x00) + appstring \
+ chr(len(messagepart2)) + chr(0x00) + messagepart2
sock.send(part2);
After pushing button. Is there way to do it too?
Thanks! I'm new to Python
Answer: Since `entry_tvip` is a method of the `Application` class and `app` is an
instance of this class, you can call `app.entry_tvip.get()`
You will not be able to do this anywhere before the `app` is created, so I
would rethink your approach.
|
convert kenneth French data to daily datetime format in python
Question: I want to integrate date from Kenneth French's website with the following
code, that works fine for monthly data. But since I need now daily data I need
to know what I have to put for the variable XYZ (in the last row of code) in
order to make it work:
import pandas.io.data
import pandas as pd
from datetime import datetime, date
io = pandas.io.data.DataReader("F-F_Research_Data_Factors_daily", "famafrench")
ff = io[0] # Bestimmung des Dictionary Teils aus der FF Zip Datei
ff.columns = ['Mkt_rf', 'SMB', 'HML', 'rf']
ff.index = [datetime(d/100, d%100, XYZ) for d in ff.index]
This is how the index looks like:
Int64Index([19260701, 19260702, 19260706, 19260707, 19260708, 19260709, 19260710, 19260712, 19260713, 19260714, 19260715, 19260716, 19260717, 19260719, 19260720, 19260721, 19260722, 19260723, 19260724, 19260726, 19260727, 19260728, 19260729, 19260730, 19260731, 19260802, 19260803, 19260804, 19260805, 19260806, 19260807, 19260809, 19260810, 19260811, 19260812, 19260813, 19260814, 19260816, 19260817, 19260818, 19260819, 19260820, 19260821, 19260823, 19260824, 19260825, 19260826, 19260827, 19260828, 19260830, 19260831, 19260901, 19260902, 19260903, 19260907, 19260908, 19260909, 19260910, 19260911, 19260913, 19260914, 19260915, 19260916, 19260917, 19260918, 19260920, 19260921, 19260922, 19260923, 19260924, 19260925, 19260927, 19260928, 19260929, 19260930, 19261001, 19261002, 19261004, 19261005, 19261006, 19261007, 19261008, 19261009, 19261011, 19261013, 19261014, 19261015, 19261016, 19261018, 19261019, 19261020, 19261021, 19261022, 19261023, 19261025, 19261026, 19261027, 19261028, 19261029, 19261030, ...], dtype='int64')
And this is how the dataframe looks like:
Mkt_rf SMB HML rf
19260701 0.10 -0.24 -0.28 0.009 # the integer 19260701 needs to get converted to a datetime copartible format such as 1926/07/01
... ... ... ... ...
20150430 -1.11 -1.04 0.73 0.000
[23467 rows x 4 columns]
I use pandas 0.16.1
Any ideas?
Answer: To convert your index to a DatetimeIndex, you can use `to_datetime`:
ff.index = pd.to_datetime(ff.index, format='%Y%m%d')
When having your dates as integers, the above works by specifying
`format='%Y%m%d'` and `to_datetime` will see the ints as a string of that
format. A small example:
In [2]: pd.to_datetime([19260701, 19260702], format='%Y%m%d')
Out[2]: DatetimeIndex(['1926-07-01', '1926-07-02'], dtype='datetime64[ns]', freq=None, tz=None)
|
How to print the first line from a traceback stack
Question: Suppose I am given the following traceback:
Traceback (most recent call last):
File "<wingdb_compile>", line 3, in <module>
File "C:\Python34\lib\ftplib.py", line 419, in login
resp = self.sendcmd('PASS ' + passwd)
File "C:\Python34\lib\ftplib.py", line 272, in sendcmd
return self.getresp()
File "C:\Python34\lib\ftplib.py", line 245, in getresp
raise error_perm(resp)
ftplib.error_perm: 530 Login incorrect.
I have managed to extract the Error details but what has stumped me is how
would I extract the line:
File "<wingdb_compile>", line 3, in <module>
I was looking at methods in the trace back package but wondered if any one had
experience with that here
Answer: The function
[`traceback.format_exc`](https://docs.python.org/2/library/traceback.html#traceback.format_exc)
is built primarily for this
> This is like `print_exc(limit)` but **_returns a string_** instead of
> printing to a file.
>>> import traceback
>>> try:
... x = 2/0
... except:
... error = traceback.format_exc()
...
>>> error
'Traceback (most recent call last):\n File "<stdin>", line 2, in <module>\nZeroDivisionError: division by zero\n'
>>> linesoferror = error.split('\n')
>>> linesoferror
['Traceback (most recent call last):', ' File "<stdin>", line 2, in <module>', 'ZeroDivisionError: division by zero', '']
So now you wanted the first line then you can simply use
>>> linesoferror[1]
' File "<stdin>", line 2, in <module>'
Voila! You have what you want
> **ALERT** \- Valid for Python 2.4.1 and above
|
How to get pixel coordinates from Feature Matching in OpenCV Python
Question: I need to get the list of the `x` and `y` coordinates of the pixels that the
feature matcher selects in the code provided. I'm using Python and OpenCV. Can
anyone help me?
img1=cv2.imread('DSC_0216.jpg',0)
img2=cv2.imread('DSC_0217.jpg',0)
orb=cv2.ORB(nfeatures=100000)
kp1,des1=orb.detectAndCompute(img1,None)
kp2,des2=orb.detectAndCompute(img2,None)
img1kp=cv2.drawKeypoints(img1,kp1,color=(0,255,0),flags=0)
img2kp=cv2.drawKeypoints(img2,kp2,color=(0,255,0),flags=0)
cv2.imwrite('m_img1.jpg',img1kp)
cv2.imwrite('m_img2.jpg',img2kp)
bf=cv2.BFMatcher(cv2.NORM_HAMMING, crossCheck=True)
matches=bf.match(des1,des2)
matches=sorted(matches, key= lambda x:x.distance)
Answer: `matches` returns a list of structures where each structure contains several
fields... among them are two important fields:
* `queryIdx` \- The index of the feature into `kp1` that matches
* `trainIdx` \- The index of the feature into `kp2` that matches
You'd use these to index into `kp1` and `kp2` and obtain the `pt` field to
obtain the `(x,y)` coordinates of the matches.
All you have to do is iterate through each structure in `matches`, append to a
list of coordinates for both `kp1` and `kp2` and you're done.
Something like this:
# Initialize lists
list_kp1 = []
list_kp2 = []
# For each match...
for mat in matches:
# Get the matching keypoints for each of the images
img1_idx = mat.queryIdx
img2_idx = mat.trainIdx
# x - columns
# y - rows
# Get the coordinates
(x1,y1) = kp1[img1_idx].pt
(x2,y2) = kp2[img2_idx].pt
# Append to each list
list_kp1.append((x1, y1))
list_kp2.append((x2, y2))
Note that I could have just done `list_kp1.append(kp1[img1_idx].pt)`, as well
as the same for `list_kp2`, but I wanted to make very clear on how to
interpret the spatial coordinates.
`list_kp1` will contain the spatial coordinates of a feature point that
matched with the corresponding position in `list_kp2`. In other words, element
`i` of `list_kp1` contains the spatial coordinates of the feature point from
`img1` that matched with the corresponding feature point from `img2` in
`list_kp2` whose spatial coordinates are in element `i`.
* * *
As a minor sidenote, I used this concept when I wrote a workaround for
[`drawMatches`](http://docs.opencv.org/modules/features2d/doc/drawing_function_of_keypoints_and_matches.html#drawmatches)
because for OpenCV 2.4.x, the Python wrapper to the C++ function does not
exist, so I made use of the above concept in locating the spatial coordinates
of the matching features between the two images to write my own implementation
of it.
Check it out if you like!
[module' object has no attribute 'drawMatches' opencv
python](http://stackoverflow.com/questions/20259025/module-object-has-no-
attribute-drawmatches-opencv-python/26227854#26227854)
|
Python: How to check the value of a non-existent list element without getting IndexError?
Question: I'm using Python's one-line conditional thus:
x = 'foo' if myList[2] is not None else 'bar'
to assign to `x` the value of an item at a certain index of a list - **if and
only if it exists** \- and a different value if it doesn't.
Here's my challenge: `myList` can have up to three elements, but won't always
have three. So if the index doesn't exist (i.e. if the index in question is 1+
greater than the size of the list), I'll obviously get an `IndexError list out
of range` before the inline conditional can assign the variable:
In [145]: myList = [1,2]
In [146]: x = 'foo' if myList[2] is not None else 'bar'
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
<ipython-input-146-29708b8c471e> in <module>()
----> 1 x = 'foo' if myList[2] is not None else 'bar'
IndexError: list index out of range
Checking the length of the list beforehand is not really an option, since I
can't know which value I'm interested in is missing (i.e. `myList` can be
missing any or all of three possible values. Knowing that it contains only
one, or two, or three elements does not help).
**Update:** the reason why I can't assign based on the length of the list is
as follows. The list can have a maximum size of 3, and **order is important**.
The values populated will be the result of three separate calls to an API. If
all calls to the API succeed, I get a full list, and everything is fine. Yet
if only two return a value, the list only contains two items, yet **I cannot
know which API call has led to the missing item** , so assigning variables is
pot luck.
So, long story short: How can I check for a non-existent list item at a
certain index, while getting to keep Python's one-line conditional?
Answer: Just test if there are enough elements:
x = 'foo' if len(myList) > 2 and myList[2] is not None else 'bar'
It doesn't matter if the first 2 elements are missing or if you have more than
3 elements. What matters is that the list is long enough to have a 3rd element
in the first place.
|
How to install scipy misc package
Question: I have installed (actually reinstalled) scipy:
10_x86_64.whl (19.8MB): 19.8MB downloaded
Installing collected packages: scipy
Successfully installed scipy
But the misc subpackage is apparently not included?
16:03:28/shared $ipython
In [1]: from scipy.misc import imread
---------------------------------------------------------------------------
ImportError Traceback (most recent call last)
<ipython-input-1-f9d3d927b58f> in <module>()
----> 1 from scipy.misc import imread
ImportError: cannot import name imread
What is the way to install the scipy.misc package?
Answer: I think you need to install PIL as well. From [the scipy.misc
docs:](http://docs.scipy.org/doc/scipy/reference/misc.html)
> Note that the Python Imaging Library (PIL) is not a dependency of SciPy and
> therefore the pilutil module is not available on systems that don’t have PIL
> installed.
|
How can I get the current time in ISO formatted string with the 'Z' as time designator instead of '+00:00'"?
Question: On Python 3.x `datetime.utcnow().isoformat()` gives no timezone designator and
`datetime.now(timezone.utc).isoformat` gives the `+00:00`. Is there any way to
force to use the `Z` (zulu timezone)?
Answer: The ~~naive~~ straighforward way is
from datetime import datetime, timezone
datetime.utcnow().isoformat()+'Z' # '2015-06-09T07:17:55.719302Z'
`datetime.utcnow()` returns a naive `datetime` on UTC , `isoformat` won't add
any timezone because there is none in the naive datetime, and then we add
manually the `'Z'` because we know that it's actually in the UTC / Zulu
timezone
or if you happen to have a timezone aware `datetime` on UTC already you can
just drop the timezone (make a copy of the `datetime` first) and the do the
`.isoformat()+'Z'`.
from datetime import datetime, timezone
datetime.now(timezone.utc).replace(tzinfo=None).isoformat()+'Z'
# '2015-06-09T07:17:55.719302Z'
If the timezone aware `datetime` is not on UTC then you need to bring it to
the UTC timezone first.
from datetime import datetime,timezone
from dateutil.tz import tzutc
datetime.now(tzoffset("BRST", -10800)).astimezone(tzutc()).replace(tzinfo=None).isoformat()+'Z'
# '2015-06-09T08:14:02.861058Z'
|
Matplotlib Crash When Figure 1 not Closed Last
Question: I am plotting mutliple figures using Matplotlib using Python 3.4.
When the multiple figures are open and I close the windows closing the first
figure last (ie once all other figures are closed) python does not crash.
If, however, I close the first figure that was plotted first and then close
the rest Python crashes.
It seems as though you need to close the windows in such an order that the
first window that was opened must be closed last. Has anyone else experienced
and is there a solution?
Here is a trivial example code that can be used to verify:
import matplotlib.pyplot as plt
plt.figure(1) # the first figure
plt.plot([1,2,3])
plt.figure(2) # a second figure
plt.plot([4,5,6])
plt.show()
Answer: The way I have managed to solve this issue has been to use Qt4 as the
matplotlib backend.
Simply add the following two lines of code after importing matplotlib.
import matplotlib as mpl
mpl.rcParams['backend'] = "qt4agg"
mpl.rcParams['backend.qt4'] = "PySide"
This is what I do on Python 3 and have no plot closing errors
|
How do I fix this sorting error?
Question: I currently have the code below but for some reason it only sorts using the
first number from the array so for example if the number was 1000 and it was
compared to a 50 the 50 would be greater then the 1000. How do i fix this?
#!/usr/local/bin/python3.4
import operator
import pygame, sys
from pygame.locals import *
import random
placement = [1, 2, 3, 4, 5]
data = [
{"score": "1000", "grade": "E", "music": "song5", "maxcombo": "1", "perfect": "20", "great": "1", "good": "20", "miss": "1"},
{"score": "200", "grade": "D", "music": "song4", "maxcombo": "2", "perfect": "20", "great": "2", "good": "20", "miss": "2"},
{"score": "500", "grade": "C", "music": "song3", "maxcombo": "3", "perfect": "20", "great": "3", "good": "20", "miss": "3"},
{"score": "400", "grade": "B", "music": "song2", "maxcombo": "4", "perfect": "20", "great": "4", "good": "20", "miss": "4"},
{"score": "300", "grade": "A", "music": "song1", "maxcombo": "5", "perfect": "20", "great": "5", "good": "20", "miss": "5"},
]
print (sorted(data, key=operator.itemgetter("score"), reverse=True))
Answer: "1000" isn't a number. It's a string whose characters happen to be digits. If
you want to sort numerically, represent your data with numbers.
data = [
{"score": 1000, "grade": "E", "music": "song5", "maxcombo": 1, "perfect": 20, "great": 1, "good": 20, "miss": 1},
#... etc
Or, if you have to keep them as strings for some reason, convert to integer in
the key function.
print (sorted(data, key=lambda row: int(row["score"]), reverse=True))
|
What Can I be Researching to speed this python scripted mysql-query up?
Question: so I spent a long time on the site yesterday to write this entire script in
python (which I had never before used). I was pleased with the results (it
worked on my tiny test-data set of 10,000 entries), but now that I'm using
production data (many million) it is incredibly slow.
Here's the code:
#!/usr/bin/env python
import sys
import MySQLdb
import argparse
parser = argparse.ArgumentParser(description="This is used to actually generate matched lists. outputs those that matched")
parser.add_argument("Database", help="The name of the database you want to run matching against")
args = parser.parse_args()
tablename = str(sys.argv[1])
mydb = MySQLdb.connect(host='localhost',
user='root',
passwd='[REDACTED]',
db='Data')
cursor = mydb.cursor()
sql = "SELECT name FROM table1 WHERE md5 IN (select md5 from %s)" %tablename
cursor.execute(sql)
data = cursor.fetchall()
for row in data :
print row[0]
#close the connection to the database.
mydb.commit()
cursor.close()
to explain how my tables look:
table1 | name | md5
table2 | md5
I'm sure there's some optimization I could do on the server itself to make
mysql faster, but my suspicion is that there's some ways I could have made
this faster in the code itself. Any suggestions on where to continue
researching this would be appreciated.
Cheers!
Answer: Do something like this:
SELECT
t1.name
FROM
table1 t1
INNER JOIN table2 t2 ON
t2.md5 = t1.md5
And you should also **index the md5 columns** on both tables!
The _in_ operator acts much like a _left outer join_ , so you are giving the
server an enormous amount of data to process when you only want the names of
the md5 columns that match!
|
Swap a character with its next character in paragraph
Question: **I have to swap a specific character appearing in paragraph to its next
character.**
let suppose that my paragraph text is:
**My name is andrew. I am very addicted to python and attains very high
knowledge about programming.**
Now, my task is to find particular character in paragraph and swap it with the
character next to it. Like, I want to swap every character 'a' with its the
character next to it. After process my paragraph should look like this:
**My nmae is nadrew. I ma very dadicted to python nad tatians very high
knowledge baout progrmaming.**
I would be very thankful if anybody define function for this in python
Answer: This will do it:
>>> import re
>>>>regex = re.compile(r'(a)(\w)')
>>>>text = 'My name is andrew. I am very addicted to python and attains very high knowledge about programming.'
>>> regex.sub(lambda(m) : m.group(2) + m.group(1), text)
'My nmae is nadrew. I ma very dadicted to python nad tatians very high knowledge baout progrmaming.'
Explanation:
(a)(\w)
Matches a, and put it on group 1, then matches another word character put in
group 2. Lambda expression for replacement switch these two groups.
If you want to match everything but spaces use :
(a)(\S)
|
Best practice for using common subexpression elimination with lambdify in SymPy
Question: I'm currently attempting to use SymPy to generate and numerically evaluate a
function and its gradient. For simplicity, I'll use the following function as
an example (keeping in mind that the real function is much lengthier):
import sympy as sp
def g(x):
return sp.cos(x) + sp.cos(x)**2 + sp.cos(x)**3
It's easy enough to numerically evaluate this function and its derivative:
import numpy as np
g_expr = sp.lambdify(x,g(x),modules='numpy')
dg_expr = sp.lambdify(x,sp.diff(g(x)),modules='numpy')
print g_expr(np.linspace(0,1,50))
print dg_expr(np.linspace(0,1,50))
For my real function, however, lambdify is slow, both in terms of generating
the numerical function and in its evaluation. As many elements in my function
are similar, I'd like to use common subexpression elimination (cse) within
lambdify to speed this process up. I know that SymPy has a built-in function
to perform cse,
>>> print sp.cse(g(x))
([(x0, cos(x))], [x0**3 + x0**2 + x0])
but don't know what syntax to use in order to utilize this result in my
lambdify function (where I'd still like to use x as my input argument):
>>> g_expr_fast = sp.lambdify(x,sp.cse(g(x)),modules='numpy')
>>> print g_expr_fast(np.linspace(0,1,50))
Traceback (most recent call last):
File "test3.py", line 34, in <module>
print g_expr1(nx1)
File "<string>", line 1, in <lambda>
NameError: global name 'x0' is not defined
Any help on how to use cse in lambdify would be appreciated. Or, if there are
better ways to speed up my gradient calculations, I'd appreciate hearing those
as well.
In case it's relevant, I'm using Python 2.7.3 and SymPy 0.7.6.
Answer: So this might not be the most optimal way to do it, but for my small example
it works.
The idea of following code is lambdifying each common subexpression and
generate a new function with possibly all arguments. I added a few additional
sin and cos terms to add possible dependencies from previous subexpressions.
import sympy as sp
import sympy.abc
import numpy as np
import matplotlib.pyplot as pl
def g(x):
return sp.cos(x) + sp.cos(x)**2 + sp.cos(x)**3 + sp.sin(sp.cos(x)+sp.sin(x))**4 + sp.sin(x) - sp.cos(3*x) + sp.sin(x)**2
repl, redu=sp.cse(g(sp.abc.x))
funs = []
syms = [sp.abc.x]
for i, v in enumerate(repl):
funs.append(sp.lambdify(syms,v[1],modules='numpy'))
syms.append(v[0])
glam = sp.lambdify(syms,redu[0],modules='numpy')
x = np.linspace(-1,5,10)
xs=[x]
for f in funs:
xs.append(f(*xs))
print glam(*xs)
glamlam = sp.lambdify(sp.abc.x,g(sp.abc.x),modules='numpy')
print glamlam(x)
print np.allclose(glamlam(x),glam(*xs))
repl contains:
[(x0, cos(x)), (x1, sin(x)), (x2, x0 + x1)]
and redu contains
[x0**3 + x0**2 + x1**2 + x2 + sin(x2)**4 - cos(3*x)]
So `funs` contains all subexpression lambdified and the list `xs` contains
each subexpression evaluated, such one can feed `glam` properly in the end.
`xs` grows with each subexpression and might turn out to be a bottle neck in
the end.
You can do the same approach on the expression of
`sp.cse(sp.diff(g(sp.abc.x)))`.
|
Python/Django Not Appending Slash
Question: For some reason Django is not appending a slash at the end of variables that
contain numeric characters:
test_A -- works (goes to test_A/)
test_1 -- does not (doesn't append the / at the end - giving me a 404)
I do have middleware installed and APPEND_SLASH = True.
Any thoughts? Thanks!
url.conf:
from django.conf.urls import patterns, url
from dashboard import views
urlpatterns = patterns('',
url(r'^$', views.index, name='index'),
url(r'^environment/(?P<environment_name_url>\w+)/$', views.environment, name='environment'),)
models.py:
from django.db import models
class Environment(models.Model):
name = models.CharField(max_length=128, unique=True)
def __str__(self):
return self.name
views.py:
def environment(request, environment_name_url):
environment_name = environment_name_url.replace('_', ' ')
context_dict = {'environment_name': environment_name}
try:
environment = Environment.objects.get(name=environment_name)
pages = Page.objects.filter(environment=environment)
context_dict['pages'] = pages
context_dict['environment'] = environment
except Environment.DoesNotExist:
pass
return render(request, 'dashboard/environment.html', context_dict)
Error:
Using the URLconf defined in dashboard_project.urls, Django tried these URL patterns, in this order:
1. ^admin/
2. ^dashboard/ ^$ [name='index']
3. ^dashboard/ ^environment/(?P<environment_name_url>\w+)/$ [name='environment']
4. media/(?P<path>.*)
The current URL, dashboard/environment/test_1, didn't match any of these.
Answer: You have to extend your regular expressions. The problem is not that the slash
is not appended, the problem is that none of the urls matches (with or without
the slash).
Simple solution, to include the dot you should update your regular expression
to also allow a dot: `url(r'^environment/(?P<environment_name_url>[\w\.]-)/$',
views.environment, name='environment'),)`
Your could improve it further to also allow a dash:
`url(r'^environment/(?P<environment_name_url>[\w\.-]+)/$', views.environment,
name='environment'),)`
The latter would even allow /test-1.1_10/
|
Django: TemplateDoesNotExist at / home.html
Question: I'm trying to create first site using Django and Udemy tutorial
([here](https://www.udemy.com/learn-django-code-accept-payments-with-
stripe/?dtcode=3Rdc8KM2WWhw#/lecture/2222730)) and I stuck on lesson 7: Home
view. After runserver i get error:
Request Method: GET
Request URL: http://127.0.0.1:8000/
Django Version: 1.8.2
Python Version: 3.4.2
Installed Applications:
('django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'profiles')
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')
Template Loader Error:
Django tried loading these templates, in this order:
Using loader django.template.loaders.filesystem.Loader:
Using loader django.template.loaders.app_directories.Loader:
/root/Documents/tryDjango/lib/python3.4/site-packages/django/contrib/ admin/templates/home.html (File does not exist)
/root/Documents/tryDjango/lib/python3.4/site-packages/django/contrib/auth/templates/home.html (File does not exist)
Traceback:
File "/root/Documents/tryDjango/lib/python3.4/site-packages/django/core/ handlers/base.py" in get_response
132. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/root/Documents/tryDjango/src/profiles/views.py" in home
7. return render(request, template, context)
File "/root/Documents/tryDjango/lib/python3.4/site-packages/django/shortcuts.py" in render
67. template_name, context, request=request, using=using)
File "/root/Documents/tryDjango/lib/python3.4/site-packages/django/template/loader.py" in render_to_string
98. template = get_template(template_name, using=using)
File "/root/Documents/tryDjango/lib/python3.4/site-packages/django/template/loader.py" in get_template
46. raise TemplateDoesNotExist(template_name)
Exception Type: TemplateDoesNotExist at /
Exception Value: home.html
I created app profiles and my structure tree looks like this:
/tryDjango
/src
/tryDjango
urls.py
setting.py
_init_.py
wsgi.py
/profiles
admin.py
models.py
_init_.py
tests.py
views.py
/static
/templates
home.html
settings.py
import os
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
SECRET_KEY = XXXX
# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True
ALLOWED_HOSTS = []
# Application definition
INSTALLED_APPS = (
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'profiles',
)
MIDDLEWARE_CLASSES = (
'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',
)
ROOT_URLCONF = 'tryDjango.urls'
TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [],
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
],
},
},
]
WSGI_APPLICATION = 'tryDjango.wsgi.application'
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
}
}
LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_L10N = True
USE_TZ = True
STATIC_URL = '/static/'
TEMPLATE_DIRS = (os.path.join(os.path.dirname(BASE_DIR), 'static', 'templates'), )
urls.py
from django.conf.urls import include, url
from django.contrib import admin
urlpatterns = [
url(r'^admin/', include(admin.site.urls)),
url(r'^$', 'profiles.views.home', name='home'),
]
views.py
from django.shortcuts import render
# Create your views here.
def home(request):
context = locals()
template = 'home.html'
return render(request, template, context)`
I also tried commands from other and here is the output:
>>>from django.conf import settings
>>>print (settings.TEMPLATE_DIRS)
('/root/Documents/tryDjango/static/templates',)
>>> from django.template import loader
>>> print(loader.get_template('home.html'))
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/root/Documents/tryDjango/lib/python3.4/site-packages/django/ template/loader.py", line 46, in get_template
raise TemplateDoesNotExist(template_name)
django.template.base.TemplateDoesNotExist: home.html
Thanks a lot! P.S I use Debian.
Answer: It's not a good idea to put your templates in your `static` because files
there will be readily available to the internet, and you probably don't want
to be exposing your raw back end to the world `;)`
Try this file structure (note that I have moved the `templates` directory):
/tryDjango
/src
/tryDjango
urls.py
setting.py
_init_.py
wsgi.py
/templates
home.html
/profiles
admin.py
models.py
_init_.py
tests.py
views.py
Django's [main template
loader](https://docs.djangoproject.com/en/1.8/ref/templates/api/#django.template.loaders.app_directories.Loader)
searches through the directories of each of the `INSTALLED_APPS`, and users
the first template in a `templates` folder that matches.
If you rely upon that (which I recommend), you will need to add `'home',` to
your `INSTALLED_APPS`.
Alternatively, the [other default template
loader](https://docs.djangoproject.com/en/1.8/ref/templates/api/#django.template.loaders.filesystem.Loader)
will look in paths you have defined for `templates` folders.
For that, you will need to add the full path to [`TEMPLATES['dirs']` in Django
1.8+](https://docs.djangoproject.com/en/1.8/ref/templates/upgrading/#the-
templates-settings) or [`TEMPLATE_DIRS` in older
versions](https://docs.djangoproject.com/en/1.7/ref/settings/#template-dirs).
|
Django login tests session problems
Question: Here are the two lines of code I'm trying to cover with tests:
from django.contrib.auth import login
from django.views.generic.edit import FormView
from accounts.forms import UsernameLoginForm
class LoginView(FormView):
form_class = UsernameLoginForm
success_url = '/'
template_name = 'login.html'
def form_valid(self, form):
login(self.request, form.get_user())
return super(LoginView, self).form_valid(form)
This seems to be the proper way to functionally implement a login form
extended from django.contrib.auth.forms.AuthenticationForm, but I had to dig
the code out of the admin login view myself so it needs decent testing.
I'm having problems getting the test environment to set the user on the
session. RequestFactory has no session support so this is what I tried:
from django.contrib.auth.models import User
from django.test import TestCase
from django.test.client import RequestFactory
import mox
from accounts.forms import UsernameLoginForm
from accounts.views import LoginView
class ViewTests(TestCase):
def test_login(self):
user = User.objects.create(username='userfoo')
view = LoginView()
# request = RequestFactory()
view.request = self.client
self.moxx = mox.Mox()
form = self.moxx.CreateMock(UsernameLoginForm)
form.get_user().AndReturn(user)
self.moxx.ReplayAll()
view.form_valid(form)
self.moxx.VerifyAll()
self.assertTrue(request.user)
And this is the error that causes:
File "/home/renoc/.virtualenvs/alc/local/lib/python2.7/site-packages/django/contrib/auth/__init__.py", line 110, in login
request.session.cycle_key()
File "/home/renoc/.virtualenvs/alc/local/lib/python2.7/site-packages/django/contrib/sessions/backends/base.py", line 283, in cycle_key
data = self._session_cache
AttributeError: 'SessionStore' object has no attribute '_session_cache'
self.client.request.session is volatile and if I try to set an attribute on it
it throws no errors but it doesn't have the attribute when accessed either.
Answer: After a lot of work I found that I could attach the session generated by
TestCase.client to the RequestFactory and have an instance I could alter. Here
is what I came up with to make my tests work.
from django.contrib.auth.models import User
from django.test import TestCase
from django.test.client import RequestFactory
import mox
from accounts.forms import UsernameLoginForm
from accounts.views import LoginView
class ViewTests(TestCase):
def setUp(self):
self.moxx = mox.Mox()
def tearDown(self):
self.moxx.UnsetStubs()
def test_login(self):
user = User.objects.create(username='userfoo')
user.backend = ''
view = LoginView()
request = RequestFactory()
request.META = {}
request.user = None
request.session = self.client.session
request.session.create()
view.request = request
form = self.moxx.CreateMock(UsernameLoginForm)
form.get_user().AndReturn(user)
self.moxx.ReplayAll()
view.form_valid(form)
self.moxx.VerifyAll()
self.assertTrue(request.user)
I hope you will still offer suggestions including why I shouldn't be doing
anything like this in the first place.
|
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