Get all (n-choose-k) combinations of length n

itertools can do this:

import itertools

for comb in itertools.combinations([1, 2, 3, 4], 3):
    print(comb)

Outputs:

(1, 2, 3)
(1, 2, 4)
(1, 3, 4)
(2, 3, 4)