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Date: Fri, 28 Nov 2014 16:04:30 +0100
Subject: Iterate over text file, discarding some lines via context manager
From: "fetchinson ." <fetchinson@googlemail.com>
To: python-list@python.org
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Hi all,

I have a feeling that I should solve this by a context manager but
since I've never used them I'm not sure what the optimal (in the
python sense) solution is. So basically what I do all the time is
this:

for line in open( 'myfile' ):
    if not line:
        # discard empty lines
        continue
    if line.startswith( '#' ):
        # discard lines starting with #
        continue
    items = line.split( )
    if not items:
        # discard lines with only spaces, tabs, etc
        continue

    process( items )

You see I'd like to ignore lines which are empty, start with a #, or
are only white space. How would I write a context manager so that the
above simply becomes

with some_tricky_stuff( 'myfile' ) as items:
    process( items )

Cheers,
Daniel


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