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Groups > comp.lang.python > #42218

Doing both regex match and assignment within a If loop?

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Hi,

I have logline that I need to test against multiple regexes. E.g.:

    import re

    expression1 = re.compile(r'....')
    expression2 = re.compile(r'....')

    with open('log.txt') as f:
        for line in f:
            if expression1.match(line):
                # Do something - extract fields from line.
            elif expression2.match(line):
                # Do something else - extract fields from line.
            else:
                # Oh noes! Raise exception.

However, in the "Do something" section - I need access to the match object itself, so that I can strip out certain fields from the line.

Is it possible to somehow test for a match, as well as do assignment of the re match object to a variable?

    if expression1.match(line) = results:
        results.groupsdict()...

Obviously the above won't work - however, is there a Pythonic way to tackle this?

What I'm trying to avoid is this:

    if expression1.match(line):
        results = expression1.match(line)

which I assume would call the regex match against the line twice - and when I'm dealing with a huge amount of log lines, slow things down.

Cheers,
Victor

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Doing both regex match and assignment within a If loop? Victor Hooi <victorhooi@gmail.com> - 2013-03-28 21:00 -0700
  Re: Doing both regex match and assignment within a If loop? Chris Rebert <clp2@rebertia.com> - 2013-03-28 21:29 -0700
  Re: Doing both regex match and assignment within a If loop? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-03-29 06:45 +0000
  Re: Doing both regex match and assignment within a If loop? Peter Otten <__peter__@web.de> - 2013-03-29 09:27 +0100
  Re: Doing both regex match and assignment within a If loop? Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-03-29 11:06 +0100
    Re: Doing both regex match and assignment within a If loop? Arnaud Delobelle <arnodel@gmail.com> - 2013-03-29 10:41 +0000
    Re: Doing both regex match and assignment within a If loop? Neil Cerutti <neilc@norwich.edu> - 2013-03-29 12:51 +0000
  Re: Doing both regex match and assignment within a If loop? Mitya Sirenef <msirenef@lightbird.net> - 2013-03-29 09:49 -0400

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