newbie question...

[Skip Montanaro]

    abs> I'm wondering what the accepted method of handling a text file's
    abs> contents are in Python. For example, the following Perl construct
    abs> is pretty standard.

    abs>     while ( <SOMEFILEHANDLE> )
    abs>     {
    abs>         # process each line as if comes off the file handle...
    abs>     }

    abs> is typical.

    abs> The equivalent Python appears to be

    abs>     somefilehandle = open( "some/file/name.text" )
    abs>     all_the_lines_in_the_file = somefilehandle.readlines()
    abs>     somefilehandle.close()

    abs>     # now process the lines in the all_the_lines_... list
    abs>     # using some prefered method (there's more than
    abs>     # one way of doing this, of course ;-)

    abs> THE BIG QUESTION: Am I understanding Python's philosophy properly?

Yeah, that's a pretty typical idiom for small files.  For larger files
something like

    somefilehandle = open( "some/file/name.text" )
    line = somefilehandle.readline()
    while line:
        dofunstuff(line)
	line = somefilehandle.readline()
     somefilehandle.close()

Before you run off and compare that with the equivalent Perl and find it
lacking in performance, I'll interject that Python does nothing fancy with
its I/O.  It's just built on top of stdio.  For larger files you *can* chunk
the input using something like

    sizehint = 10**6
    somefilehandle = open( "some/file/name.text" )
    lines = somefilehandle.readlines(sizehint)
    while lines:
        for line in lines:
	    dofunstuff(line)
	lines = somefilehandle.readlines(sizehint)
     somefilehandle.close()

It's not as succinct as the simpler idioms, but somewhat more efficient.

Skip Montanaro | http://www.mojam.com/
skip at mojam.com | http://www.musi-cal.com/
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