python - Get all unique combinations from list of permutations -

tl/dr

given x = {(a,b),(b,c),(d,e),(b,a),(c,b)} (where x set)

how filter subtuples show unique combination (instead of unique permutation) such x becomes {(a,b),(b,c),(d,e))}

longer form

somewhat of inverse problem of combination/permutation questions on here.

i have set of tuples (outer tuples), each tuple has 2 elements, both of tuples (inner tuples), , each sub-tuple has 2 elements, both of integers.

as example, set 3 elements might like

x = { ( (1,2),(2,3) ), ( (1,3),(1,2) ), ( (2,3),(1,2) ) } 

while outer tuples unique, i'd build subset contains set of unqiue tuples order of 2 inner tuples irrelevant (i.e. set of unique combinations). in example above reduce to;

x = { ( (1,2),(2,3) ), ( (1,3),(1,2) )} 

because

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

are both combinations of (1, 2) , (2,3).

there obvious brute-force/for-loop approaches don't feel pythonic.

maybe leveraging itertools , map?

you can apply sorted function on elements using map , use set comprehension unique elements :

>>> new={tuple(i) in map(sorted,x)} >>> new set([('b', 'c'), ('a', 'b'), ('d', 'e')]) 

but note since sorted convert elements list need reverse them tuple because lists not hashable.