In python, when I write:
L = [2,2,3]
list(itertools.combinations(L, 2))
I get this:
[(2, 2), (2, 3), (2, 3)]
I want to get only this:
[(2, 2), (2, 3)]
That is, each combination should appear only once, even though the original list contains two 2’s.
What is an efficient way to get each subset of L (of size 2) only once?
What I tried:
list(itertools.combinations(set(L), 2))
returns only:
[(2, 3)]
This is not good – I want to get the (2,2) too, since it is a subset of L.
list(itertools.combinations_with_replacement(set(L), 2))
returns:
[(2, 2), (2, 3), (3, 3)]
This is not good – I do not need the (3,3), since it is not a subset of L.
>Solution :
from more_itertools import distinct_combinations
print(*distinct_combinations([2, 2, 3], 2))
Output:
(2, 2) (2, 3)
Documentation, which says:
Equivalent to
set(combinations(iterable)), except duplicates are not generated and thrown away. For larger input sequences this is much more efficient.