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Groups > comp.lang.python > #3741

Groups in regular expressions don't repeat as expected

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Here's something that surprised me about Python regular expressions.

 >>> krex = re.compile(r"^([a-z])+$")
 >>> s = "abcdef"
 >>> ms = krex.match(s)
 >>> ms.groups()
('f',)

The parentheses indicate a capturing group within the
regular expression, and the "+" indicates that the
group can appear one or more times.  The regular
expression matches that way.  But instead of returning
a captured group for each character, it returns only the
last one.

The documentation in fact says that, at

http://docs.python.org/library/re.html

"If a group is contained in a part of the pattern that matched multiple 
times, the last match is returned."

That's kind of lame, though. I'd expect that there would be some way
to retrieve all matches.

					John Nagle

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Groups in regular expressions don't repeat as expected John Nagle <nagle@animats.com> - 2011-04-20 12:20 -0700
  Re: Groups in regular expressions don't repeat as expected Neil Cerutti <neilc@norwich.edu> - 2011-04-20 19:23 +0000
    Re: Groups in regular expressions don't repeat as expected John Nagle <nagle@animats.com> - 2011-04-20 13:34 -0700
      Re: Groups in regular expressions don't repeat as expected Neil Cerutti <neilc@norwich.edu> - 2011-04-21 13:16 +0000
        Re: Groups in regular expressions don't repeat as expected John Nagle <nagle@animats.com> - 2011-04-24 12:43 -0700
  Re: Groups in regular expressions don't repeat as expected MRAB <python@mrabarnett.plus.com> - 2011-04-20 21:03 +0100
  Re: Groups in regular expressions don't repeat as expected Vlastimil Brom <vlastimil.brom@gmail.com> - 2011-04-21 15:57 +0200
  Re: Groups in regular expressions don't repeat as expected Vlastimil Brom <vlastimil.brom@gmail.com> - 2011-04-21 20:36 +0200

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