Difference between revisions of "Python"
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== Key, Values of dicts == | == Key, Values of dicts == | ||
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+ | ah iteritems() ... | ||
>>> knights = {'gallahad': 'the pure', 'robin': 'the brave'} | >>> knights = {'gallahad': 'the pure', 'robin': 'the brave'} | ||
>>> for k, v in knights.iteritems(): | >>> for k, v in knights.iteritems(): | ||
... print k, v | ... print k, v | ||
− | |||
= Debugging = | = Debugging = |
Revision as of 01:35, 12 November 2009
Contents
Intro
This cheat sheet helps troubleshoot common problems...
Some good documentation source:
- http://www.python.org/doc/2.5.4/download/
- apprendre a programmer avec python by gerard swinnen (french, free PDF on the net)
Tricks
content of objects
Finding what's in an object
>>> dir(obj)
Key, Values of dicts
ah iteritems() ...
>>> knights = {'gallahad': 'the pure', 'robin': 'the brave'} >>> for k, v in knights.iteritems(): ... print k, v
Debugging
See http://pythonconquerstheuniverse.wordpress.com/category/the-python-debugger/
import pdb pdb.set_trace()
Editor tricks
Emacs
See http://python.about.com/b/2007/09/24/emacs-tips-for-python-programmers.htm
- C-c <: Shift the region to the left
- C-c >: Shift the region to the right
HOW TO
Modules & Extensions: distutils
One mention, sometime you get this error message when building your extension under Mac OS X:
/usr/bin/ld: can't locate file for: -lnameofmylib
This seems to be a weird problem with Mac OS X where even if the library (here a dynamic library ending with .dylib) is in /usr/lib, it won't be "seen" by the ld linker. To mitigate this problem, create a link in /usr/local/lib/ to the /usr/lib/XXXX.dylib library and add the path in the setup.py file.
Here is a sample setup.py that fixes that:
""" setup.py Created by Philippe Langlois on 2009-11-02. Copyright (c) 2009 Philippe Langlois. All rights reserved. """ from distutils.core import setup, Extension setup(name='pysctp', version='0.5', py_modules=['sctp'], ext_modules=[Extension('pysctp', sources=['_sctp.c'], include_dirs=['.', '/usr/include'], libraries=['sctp'], library_dirs=['/usr/lib/', '/usr/local/lib/'], ) ], data_files=['_sctp.h'], author='Elvis Pfutzenreuter', author_email='epx __AAAAATTTT_____ epx.com.br', maintainer='Philippe Langlois', maintainer_email='Philippe.Langlois __AAAAATTT____ gmail.com', )
Problems
I installed some modules / packages and can't load them
echo $PYTHONPATH
$ python Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53) [GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import sys for i in sys.path: print i
You can add a .pth file in one of the already loaded dir: see http://djangotricks.blogspot.com/2008/09/note-on-python-paths.html
like:
# cat > /Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/others.pth /Library/Python/2.5/site-packages/ ^D