module re, how to map match group names to their int index

[Harald Kirsch]

Regular expressions allow to give matching subgroups a name, e.g.:

>>> import re
>>> r = re.compile(" *(?P<X>[a-zA-Z0-9]+) *")
>>> m = r.search("   as9asdfA  ")

This allows to extract the parenthesised match by name

>>> m.group('X')
'as9asdfA'

instead of by index

>>> m.group(1)
'as9asdfA'

I would like to have the mapping from the index to the name, i.e. if
m.group(i) matches, I would like to know if there is a name
corresponding to i. In the above example this would give me "X" for
i==1. I can't find anything obvious in the re module.

Do I really have to do things like

  if m.group(1)==m.group('X'):
        # found it

Harald Kirsch

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Harald Kirsch   | kirschh at lionbioscience.com | "How old is the epsilon?"
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