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What is the purpose of the single underscore “_” variable in Python?
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_ has 5 main conventional uses in Python:
To hold the result of the last executed expression(/statement) in an interactive
interpreter session. This precedent was set by the standard CPython
interpreter, and other interpreters have followed suit
As a general...
How to delete an item in a list if it exists?
...ed, EAFP style:
This shoot-first-ask-questions-last attitude is common in Python. Instead of testing in advance if the object is suitable, just carry out the operation and catch relevant Exceptions:
try:
some_list.remove(thing)
except ValueError:
pass # or scream: thing not in some_list!
e...
Installing PIL with pip
I am trying to install PIL (the Python Imaging Library) using the command:
21 Answers
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Where in a virtualenv does the custom code go?
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virtualenv provides a python interpreter instance, not an application instance. You wouldn't normally create your application files within the directories containing a system's default Python, likewise there's no requirement to locate your applic...
Python: Continuing to next iteration in outer loop
...there are any built-in ways to continue to next iteration in outer loop in python. For example, consider the code:
8 Answ...
open read and close a file in 1 line of code
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You don't really have to close it - Python will do it automatically either during garbage collection or at program exit. But as @delnan noted, it's better practice to explicitly close it for various reasons.
So, what you can do to keep it short, simple and exp...
How to uninstall editable packages with pip (installed with -e)
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At {virtualenv}/lib/python2.7/site-packages/ (if not using virtualenv then {system_dir}/lib/python2.7/dist-packages/)
remove the egg file (e.g. distribute-0.6.34-py2.7.egg) if there is any
from file easy-install.pth, remove the corresponding l...
Django DB Settings 'Improperly Configured' Error
Django (1.5) is workin' fine for me, but when I fire up the Python interpreter (Python 3) to check some things, I get the weirdest error when I try importing - from django.contrib.auth.models import User -
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How to convert a dictionary to query string in Python?
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Python 3
urllib.parse.urlencode(query, doseq=False, [...])
Convert a mapping object or a sequence of two-element tuples, which may contain str or bytes objects, to a percent-encoded ASCII text string.
— Pytho...
String comparison in Python: is vs. == [duplicate]
I noticed a Python script I was writing was acting squirrelly, and traced it to an infinite loop, where the loop condition was while line is not '' . Running through it in the debugger, it turned out that line was in fact '' . When I changed it to !='' rather than is not '' , it worked fine.
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