no way to compare when less than two revisions

Differences

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

@@ Line 1: / Line 1: @@
+====== Python ======
+Man, there's too much to do and note.  Logging some stuff to investigate later...
+  * [[http://pycon.blogspot.com/2011/12/announcing-pycon-2012-tutorials.html|2011 PyCon tutorials announcement]] further details at the [[https://us.pycon.org/2012/schedule/lists/tutorials/|tutorial list]].
+  * They mention using [[http://ipython.org/|IPython]] enhanced shell.  Hmm.
+  * [[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]].
+  * Of course, there's getting Python running under Xampp. [[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]]
+  * 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]].
+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]].
+This [[http://stackoverflow.com/questions/231767/the-python-yield-keyword-explained/231855#231855|Explanation of Python "Yield"]] also mentions (at the bottom) explanations for decorators and metaclasses.
+Would be good to experiment with [[http://pingswept.org/2009/01/24/least-squares-polynomial-fitting-in-python/|least-squares polynomial fitting in Python]].
+===== Data Analysis =====
+Looks like I should dive into:
+  * [[http://docs.scipy.org/doc/|NumPy]]
+  * [[http://pandas.pydata.org/|Pandas]]
+  * [[http://ipython.org/|IPython]].  (As seen above.)
+===== Template Files to Start With =====
+You have some template files in svn:
+<code>
+/Code/python_templates/trunk/make_standalone_application.bat
+/Code/python_templates/trunk/setup.py
+/Code/python_templates/trunk/template_cron_job.py
+/Code/python_templates/trunk/template_gui_app.py
+/Code/python_templates/trunk/template_gui_app_with_worker_thread.py
+</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"
+</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>
+===== For / Else (Nobreak) =====
+Python has a [[http://nedbatchelder.com/blog/201110/forelse.html|For/Else keyword]] that should have been called, "nobreak."
+===== Sorting =====
+From an old [[http://dblume.livejournal.com/28319.html|note-to-self]]...
+<code python>
+import operator
+rows.sort(key=operator.itemgetter(4))
+# or
+rows.sort(lambda x, y : x[4] == y[4] and cmp(x[2],y[2]) or cmp(x[4], y[4]))
+</code>
+...not like I could just find the same info at the [[http://wiki.python.org/moin/HowTo/Sorting|Python wiki]] or anything. :-P
+===== Prepopulating lists with objects =====
+Remember when you lost a couple of hours thinking that the following line created a list of objects.
+<code python>
+    l = [Obj()] * n
+</code>
+It doesn't. It creates a list of references to one object.
+What you meant to write was this:
+<code python>
+    l = [Obj() for _ in range(n)]
+</code>
+===== Linux script that takes either stdin or files =====
+<code python>
+if __name__=='__main__':
+    if len(sys.argv) < 2:
+        # Process lines coming from stdin.
+        while 1:
+            line = sys.stdin.readline()
+            if not line:
+                break
+            my_process_line( line.rstrip() )
+    else:
+        # Process lines of the files specified.
+        for fname in sys.argv[1:]:
+            if not os.path.exists( fname ):
+                treat_argument_as_literal( fname )
+                continue
+            with open( fname, 'r' ) as f:
+                while 1:
+                    line = f.readline()
+                    if not line:
+                        break
+                    my_process_line( line.rstrip() )
+</code>
+===== The With statement =====
+[[http://amix.dk/blog/post/19663#Making-ugly-code-more-beautiful-using-Pythons-with-statement|Making code more beautiful with "with"]].  (Also mentions yield.)
+===== timeit =====
+<code python>
+import timeit
+def Use_a():
+    pass
+def Use_b():
+    pass
+def Run_all_tests():
+    my_setup()
+    Use_a()
+    Use_b()
+if __name__ == '__main__':
+#    t = timeit.timeit( 'Run_all_tests()', 'from __main__ import Run_all_tests', number=1 )
+#    print dir( t )
+#    print t
+    t = timeit.Timer( 'Run_all_tests()', 'from __main__ import Run_all_tests' )
+    print t.timeit()
+</code>
+When diving in, cProfile may come in handy.
+<code python>
+import cProfile
+def my_function():
+    # Complicated stuff
+    pass
+if __name__ == '__main__':
+    cProfile.run( "my_function()" )
+</code>
+===== Dynamically Calculating Column Size ======
+[[http://stackoverflow.com/questions/3685195/line-up-columns-of-numbers-print-output-in-table-format|Line up columns]]
+<code python>
+data = '''\
+127 34 23 45567
+12 4 4 45
+2 1 444 567'''
+# Split input data by row and then on spaces
+rows = [ line.strip().split(' ') for line in data.split('\n') ]
+# Reorganize data by columns
+cols = zip(*rows)
+# Compute column widths by taking maximum length of values per column
+col_widths = [ max(len(value) for value in col) for col in cols ]
+# Create a suitable format string
+format = ' '.join(['%%%ds' % width for width in col_widths ])
+# Print each row using the computed format
+for row in rows:
+  print format % tuple(row)
+</code>
+Which outputs:
+<code>
+127 34  23 45567
+  12  4   4    45
+   2  1 444   567
+</code>
+Also, here's a [[http://knowledgestockpile.blogspot.com/2011/01/string-formatting-in-python_09.html|nice summary of string formatting in Python]].
+===== Different Types of Objects =====
+<code python>
+class A:
+    """ Old, obsolete. """
+    def __init__(self):
+        self.__m_x = 0
+    def getx(self):
+        return self.__m_x
+    def setx(self, x):
+        if x < 0: x = 0
+        self.__m_x = x
+    x = property( getx, setx )
+class B:
+    """ Old; very small, was for for multitudes of objects. """
+    __slots__ = [ "__m_x" ]
+    def __init__(self):
+        self.__m_x = 0
+    def getx(self):
+        return self.__m_x
+    def setx(self, x):
+        if x < 0: x = 0
+        self.__m_x = x
+    x = property( getx, setx )
+class C(object):
+    """ New, reccommended. """
+    def __init__(self):
+        self.__x = 0
+    def getx(self):
+        return self.__x
+    def setx(self, x):
+        if x < 0: x = 0
+        self.__x = x
+    x = property( getx, setx )
+</code>
+====== TODO ======
+TODO Link to my tips from LiveJournal and GMail, and why I chose which timing modules.
+Touching this page to see if the indexmenu will update its data.