Combinations and Permutations

>>> items = ['a', 'b', 'c']
>>> from itertools import permutations
>>> permutations(items)

>>> for p in permutations(items):
...     print(p)
...
('a', 'b', 'c')
('a', 'c', 'b')
('b', 'a', 'c')
('b', 'c', 'a')
('c', 'a', 'b')
('c', 'b', 'a')
>>> for p in permutations(items, 2):
...     print(p)
...
('a', 'b')
('a', 'c')
('b', 'a')
('b', 'c')
('c', 'a')
('c', 'b')
>>> from itertools import combinations
>>> for c in combinations(items, 3):
...     print c
...
('a', 'b', 'c')
>>> for c in combinations(items, 2):
...     print c
...
('a', 'b')
('a', 'c')
('b', 'c')
>>> for c in combinations(items, 1):
...     print c
...
('a',)
('b',)
('c',)
>>> from itertools import combinations_with_replacement
>>> for c in combinations_with_replacement(items, 3):
...     print c
...
('a', 'a', 'a')
('a', 'a', 'b')
('a', 'a', 'c')
('a', 'b', 'b')
('a', 'b', 'c')
('a', 'c', 'c')
('b', 'b', 'b')
('b', 'b', 'c')
('b', 'c', 'c')
('c', 'c', 'c')