Source: 📖 Effective Python item 36

itertools.combinations_with_replacement

This function is the same as itertools.combinations, but items from the iterator are also combined with themselves:

it = itertools.combinations_with_replacement([1, 2, 3, 4], 2)
print(list(it))

>>>
[(1, 1),
 (1, 2),
 (1, 3),
 (1, 4),
 (2, 2),
 (2, 3),
 (2, 4),
 (3, 3),
 (3, 4),
 (4, 4)]

See also:

• itertools.combinations