I know that I can use itertools.permutation to get all permutation of size r.
But, for itertools.permutation([1,2,3,4],3)
it will return (1,2,3)
as well as (1,3,2)
.
I want to filter those repetitions (i.e obtain combinations)
Is there a simple way to get all permutations (of all lengths)?
How can I convert itertools.permutation()
result to a regular list?
Use itertools.combinations
and a simple loop to get combinations of all size.
combinations
return an iterator so you've to pass it to list()
to see it's content(or consume it).
>>> from itertools import combinations
>>> lis = [1, 2, 3, 4]
for i in xrange(1, len(lis) + 1): # xrange will return the values 1,2,3,4 in this loop
print list(combinations(lis, i))
...
[(1,), (2,), (3,), (4,)]
[(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
[(1, 2, 3), (1, 2, 4), (1, 3, 4), (2, 3, 4)]
[(1,2,3,4)]