what is regular expression capture group in python code example

Example: python named group regex example

>>> re.search(r'(?P<name>[^-]+)-(?P<ver>\d.\d.\d-\d+).tar.gz', 'package_name-1.2.3-2004.tar.gz').groupdict()
{'name': 'package_name', 'ver': '1.2.3-2004'}