import regex as re

regex 是一个向后兼容 re 的功能更强大的 Python 正则库
支持重复的 group names, 从此不再为 error: redefinition of group name … 所困扰

>>> # With optional groups:
>>>
>>> # Both groups capture, the second capture 'overwriting' the first.
>>> m = regex.match(r"(?P<item>\w+)? or (?P<item>\w+)?", "first or second")
>>> m.group("item")
'second'
>>> m.captures("item")
['first', 'second']
>>> # Only the second group captures.
>>> m = regex.match(r"(?P<item>\w+)? or (?P<item>\w+)?", " or second")
>>> m.group("item")
'second'
>>> m.captures("item")
['second']
>>> # Only the first group captures.
>>> m = regex.match(r"(?P<item>\w+)? or (?P<item>\w+)?", "first or ")
>>> m.group("item")
'first'
>>> m.captures("item")
['first']
>>>
>>> # With mandatory groups:
>>>
>>> # Both groups capture, the second capture 'overwriting' the first.
>>> m = regex.match(r"(?P<item>\w*) or (?P<item>\w*)?", "first or second")
>>> m.group("item")
'second'
>>> m.captures("item")
['first', 'second']
>>> # Again, both groups capture, the second capture 'overwriting' the first.
>>> m = regex.match(r"(?P<item>\w*) or (?P<item>\w*)", " or second")
>>> m.group("item")
'second'
>>> m.captures("item")
['', 'second']
>>> # And yet again, both groups capture, the second capture 'overwriting' the first.
>>> m = regex.match(r"(?P<item>\w*) or (?P<item>\w*)", "first or ")
>>> m.group("item")
''
>>> m.captures("item")
['first', '']

此外，regex 还支持模糊匹配等操作
更多功能，移步 pypi