[Python-Dev] a feature i'd like to see in python #2: indexing of match objects

[Steve Holden]

Martin v. Löwis wrote:
> Fredrik Lundh schrieb:
>>>> match groups are numbered 1..N, not 0..(N-1), in both the API and in the 
>>>> RE syntax (and we don't have much control over the latter).
>>> py> m = re.match("a(b)","ab")
>>> py> m.group(0)
>>> 'ab'
>>> py> m.group(1)
>>> 'b'
>> 0 isn't a group, it's an alias for the full match.
> 
> So what is the proper term for the things that the .group() method
> returns? According to
> 
> http://docs.python.org/lib/match-objects.html
> 
> it returns "subgroups of the match".
> 
> So the things to be indexed in this proposal are subgroups of the
> match.
> 
Precisely. But your example had only one group "(b)" in it, which is 
retrieved using m.group(1). So the subgroups are numbered starting from 
1 and subgroup 0 is a special case which returns the whole match.

I know what the Zen says about special cases, but in this case the rules 
were apparently broken with impunity.

regards
  Steve
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