The answer to Javascript regex question Return the part of the regex that matched is "No, because compilation destroys the relationship between the regex text and the matching logic."
But Python preserves Match Objects, and re.groups() returns the specific group(s) that triggered a match. It should be simple to preserve the regex text of each group as part of a Match Object and return it, but there doesn't appear to be a call to do so.
import re
pat = "(^\d+$)|(^\w+$)|(^\W+$)"
test = ['a', 'c3', '36d', '51', '29.5', '#$%&']
for t in test:
m = re.search(pat, t)
s = (m.lastindex, m.groups()) if m else ''
print(str(bool(m)), s)
This returns:
True (2, (None, 'a', None))
True (2, (None, 'c3', None))
True (1, ('51', None, None))
False
True (3, (None, None, '#$%&'))
The compiler obviously knows that there are three groups in this pattern. Is there a way to extract the subpattern in each group in a regex, with something like:
>>> print(m.regex_group_text)
('^\d+$', '^\w+$', '^\W+$')
Yes, it would be possible to write a custom pattern parser, for example to split on '|' for this particular pattern. But it would be far easier and more reliable to use the re compiler's understanding of the text in each group.