import itertools import re def pairwise(iterable): "s -> (s0,s1), (s1,s2), (s2, s3), ..." a, b = itertools.tee(iterable) next(b, None) return zip(a, b) text = "This module implements a number of iterator building blocks inspired by constructs from APL, Haskell, and SML. Each has been recast in a form suitable for Python." for pair in pairwise(re.split("\W", text)): print(pair)