[[Python]]
 

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

python:python [2013/04/15 09:28]
dblume [Linux or Bash Tips]
python:python [2015/04/19 14:05] (current)
dblume [Python]
Line 7: Line 7:
   * [[http://pytools.codeplex.com/releases/view/76089|Python Tools for Visual Studio 2010]].   * [[http://pytools.codeplex.com/releases/view/76089|Python Tools for Visual Studio 2010]].
   * [[http://wiki.python.org/moin/PythonSpeed/PerformanceTips|Python Performance Tips at the Python wiki]].   * [[http://wiki.python.org/moin/PythonSpeed/PerformanceTips|Python Performance Tips at the Python wiki]].
-  * Of course, there's getting Python running under Xampp. [[xampp]]+  * Of course, there's [[:xampp|getting Python running under Xampp]].
   * There's [[http://www.infoworld.com/d/application-development/pillars-python-six-python-web-frameworks-compared-169442|A comparison of CubicWeb, Django, Pyramid, Web.py, Web2py, and Zope 2]]   * There's [[http://www.infoworld.com/d/application-development/pillars-python-six-python-web-frameworks-compared-169442|A comparison of CubicWeb, Django, Pyramid, Web.py, Web2py, and Zope 2]]
   * Look into the microframework [[http://flask.pocoo.org/|Flask]]. Here's a [[http://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-world|tutorial on making a blog with it]].   * Look into the microframework [[http://flask.pocoo.org/|Flask]]. Here's a [[http://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-world|tutorial on making a blog with it]].
 +  * [[https://dataset.readthedocs.org/en/latest/|dataset]], an abstraction layer above relational databases.
 +  * [[http://docopt.org/|docopt]] for a stupidly easy and correct command-line interface description language.
 +  * [[http://stevenloria.com/python-best-practice-patterns-by-vladimir-keleshev-notes/|Best practices]] by Vladimir Keleshev.
 +  * [[https://twitter.com/brandon_rhodes/status/449938490516860928|You can ask a new-style class for its .__subclasses__()]] It uses weak references. Look at [[https://gist.github.com/etrepum/9862280|this interesting example with a child class inside a method]].
 +  * A Power Point deck by Alex Martelli describing [[http://www.aleax.it/yt_pydi.pdf|Dependency Injection vs. Template Method (override base method) vs. Monkey Patching]].
 +  * [[http://stackoverflow.com/questions/101268/hidden-features-of-python|Hidden Features of Python]] at StackOverflow
 +  * [[http://chriskiehl.com/article/parallelism-in-one-line|Parallelism in one line]]
  
 Would be nice to create a binary search in text files in Python.  Maybe based on an answer deep in [[http://stackoverflow.com/questions/744256/reading-huge-file-in-python|Reading Huge File in Python]]. Would be nice to create a binary search in text files in Python.  Maybe based on an answer deep in [[http://stackoverflow.com/questions/744256/reading-huge-file-in-python|Reading Huge File in Python]].
Line 23: Line 30:
   * [[http://pandas.pydata.org/|Pandas]]   * [[http://pandas.pydata.org/|Pandas]]
   * [[http://ipython.org/|IPython]].  (As seen above.)   * [[http://ipython.org/|IPython]].  (As seen above.)
 +
 ===== Template Files to Start With ===== ===== Template Files to Start With =====
  
Line 35: Line 43:
 </code> </code>
  
-===== Linux or Bash Tips ===== 
  
-Useful bash command for finding strings within python files... 
- 
-<code bash> 
-find . -name \*.py -type f -print0 | xargs -0 grep -nI "timeit" 
-</code> 
- 
-Interesting way to use ''grep -v'' to remove paths from a list generated by ''find''.  Not sure about the escaped ''|'' character, though... 
- 
-<code bash> 
-#!/bin/bash 
-find $PWD -regex ".*\.[hcHC]\(pp\|xx\)?" | \ 
-    grep -v " \|unwantedpath/unwantedpath2\|unwantedpath3" > cscope.files 
-cscope -q -b 
-</code> 
- 
-And these two have nothing to do with Python.  Here's how to find if a symbol is in a library, and how to search lots of object files and print the filename above the search... 
- 
-<code bash> 
-nm obj-directory/libmyobject.a | c++filt | grep Initialize_my_obj 
-find bindirectory/ -name \*.a -exec nm /dev/null {} \; 2>/dev/null | \ 
-    c++filt | grep -P "(^bindirectory.*\.a|T Initialize_my_obj)" 
-</code> 
- 
-Also handy to merge two streams together... 
- 
-<code bash> 
-( cat file1 && cat file2 ) | sort 
-</code> 
- 
-When a little quick math is needed, use ''bc'' 
-<code bash> 
-$ bc <<< "obase=16;ibase=10;15" 
-F 
-$ bc -l <<< 1/3 
-.33333333333333333333 
-$ bc <<< "scale=2; 1/3" 
-.33 
-$ bc <<< "obase=10;ibase=16;B" 
-11 
-</code> 
- 
-and, when coverting from hex to dec... 
- 
-<code bash> 
-echo $((0x2dec)) 
-</code> 
- 
-But, then again, does that really seem easier than, 
- 
-<code> 
-python -c "print int('B',16)" 
-</code> 
- 
-There's a bash way to calculate how many days ago a date was: 
- 
-<code bash> 
-$ echo $(( ($(date +%s) - $(date -d "2012-4-16" +%s)) / 86400 )) 
-</code> 
- 
-And a Python way... 
- 
-<code python> 
-python -c "import datetime; print (datetime.date.today() - datetime.date( 2012, 4, 16 )).days" 
-</code> 
- 
-And for displaying lines to get cut instead of wrapped: 
- 
-<code bash> 
-cat_one_line_per_row() { 
-  cat "$@" | expand | cut -b1-$COLUMNS 
-} 
-</code> 
- 
-ctags's man page says that one of its bugs is that it has too many options.  Ain't that the truth.  Make note of the obscure flag here, ''--c++-kinds=+p'', that tells ctags to process prototypes and method declarations. 
- 
-<code bash> 
-ctags -n --if0=yes --c++-kinds=+p --langmap=c++:+.inl.lst \ 
-    --langmap=asm:+.inc --file-tags=yes -R --extra=fq \ 
-    --exclude=unwanted_file.lst \ 
-    --exclude='*unwanted-directory*/*' \ 
-    --regex-C++='/^.*CINIT.(.+),.*,.*,.*/CURLOPT_\1/' 
-</code> 
- 
-When it's desirable to clip output to exactly the width of the window: 
- 
-<code bash> 
-alias clip="expand | cut -b1-\$COLUMNS" 
-</code> 
 ===== For / Else (Nobreak) ===== ===== For / Else (Nobreak) =====
  
Line 186: Line 105:
  
 [[http://amix.dk/blog/post/19663#Making-ugly-code-more-beautiful-using-Pythons-with-statement|Making code more beautiful with "with"]].  (Also mentions yield.) [[http://amix.dk/blog/post/19663#Making-ugly-code-more-beautiful-using-Pythons-with-statement|Making code more beautiful with "with"]].  (Also mentions yield.)
 +
 +===== cProfile vs. line_profiler and kernprof =====
 +
 +Raymond Hettinger [[https://twitter.com/raymondh/status/341010756101341187|likes Robert Kern's line_profiler much better than profile and cProfile]].
 +
 +Here it is: [[http://pythonhosted.org/line_profiler/|line_profiler and kernprof]]
  
 ===== timeit ===== ===== timeit =====
Line 307: Line 232:
  
     x = property( getx, setx )     x = property( getx, setx )
 +</code>
 +
 +====== filelock ======
 +
 +Evan Fosmark has a filelock module.  But here's a quick and dirty implementation of a lock that uses the current file:
 +
 +<code python>
 +import os
 +import fcntl
 +import inspect
 +# Maybe use os.path.abspath(__file__) ?
 +with open(os.path.abspath inspect.getfile(inspect.currentframe())), 'r') as f:
 +    try:
 +        fcntl.flock(f, fcntl.LOCK_EX)
 +        call_that_cannot_be_concurrent()
 +    finally:
 +        fcntl.flock(f, fcntl.LOCK_UN)
 +</code>
 +
 +====== Fibonacci Generator with Itertools ======
 +
 +<code python>
 +import itertools
 +
 +def fib(n):
 +    """Print a Fibonacci series up to n."""
 +    a, b = 0, 1
 +    while True:
 +        yield a
 +        b = a + b
 +        yield b
 +        a = a + b
 +
 +if __name__ == '__main__': 
 +    for x in itertools.islice(fib(), 5):
 +        print x
 +
 +#    for i in range( 5 ):
 +#        print i, fib( i )
 </code> </code>
  
python/python.1366043334.txt.gz · Last modified: 2013/04/15 09:28 by dblume
 
Recent changes RSS feed Driven by DokuWiki