all possible phase combination

Question

Suppose, I have a list of

1,1

and it can take either + or - sign. So the possible combination would be 2 to the power 2.

 1  1
 1 -1
-1  1
-1 -1

Similarly, I have a list of

1,1,1

and it can take either + or - sign. So the possible combination would be 2 to the power 3.

-1   1  -1
-1   1   1
 1   1   1
 1  -1   1
-1  -1  -1
 1   1  -1
 1  -1  -1
-1  -1   1

In python, how can I do that using itertools or any other methods. Any help please.

Answer 1

>>> import itertools
>>> lst = [1,1,1]
>>> for xs in itertools.product([1,-1], repeat=len(lst)):
...     print([a*b for a,b in zip(lst, xs)])
... 
[1, 1, 1]
[1, 1, -1]
[1, -1, 1]
[1, -1, -1]
[-1, 1, 1]
[-1, 1, -1]
[-1, -1, 1]
[-1, -1, -1]

Answer 2

You can do:

from itertools import combinations
size = 3
ans = list(set(combinations([-1,1]*size,size)))
#[(1, 1, -1),
# (-1, 1, 1),
# (-1, -1, 1),
# (1, -1, -1),
# (1, -1, 1),
# (-1, 1, -1),
# (1, 1, 1),
# (-1, -1, -1)]

This approach also gives the same result with permutations.