Groups in regular expressions don't repeat as expected

MRAB python at mrabarnett.plus.com
Wed Apr 20 22:03:48 CEST 2011


On 20/04/2011 20:20, John Nagle wrote:
> 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.
>
You should take a look at the regex module on PyPI. :-)



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