Python's re#findall

re.py

import re
# returns a list of 2-tuples: [('a', 'b'), ('c', 'd'), ('e', 'f')]
re.findall(r'([a-z])\d([a-z])\s', 'a1b c2d e3f ')

# returns a list of strings: ['1', '2', '3']
re.findall(r'[a-z](\d)[a-z]\s', 'a1b c2d e3f ')