Python combination with replacement

问题:

Below is my code

import itertools
a = [1,2,3]
for i in itertools.combination_with_replacement(a,3):
    print i

Output

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

Only 10 result is print out, but by formula, it should be 3^3 = 27 output.

So may i know, how to get the other output?
Sincerely thank for your time and suggestion.

回答1:

You want cartesian product, not combinations.

import itertools
print list(itertools.product([1, 2, 3], repeat=3))