itertools-examples.py

>>> # Calculate all profucs of an input
>>> list(itertools.product('abc', repeat=2))
[('a', 'a'), ('a', 'b'), ('a', 'c'), 
 ('b', 'a'), ('b', 'b'), ('b', 'c'), 
 ('c', 'a'), ('c', 'b'), ('c', 'c')]
 
>>> # Calculate all permutations
>>> list(itertools.permutations('abc'))
[('a', 'b', 'c'), ('a', 'c', 'b'), ('b', 'a', 'c'), 
 ('b', 'c', 'a'), ('c', 'a', 'b'), ('c', 'b', 'a')]

>>> # Take elements for iterator as long as predicate is True
>>> list(itertools.takewhile(lambda x: x<5, [1,4,6,4,1]))
[1, 4]