python - Getting unique tuples from a list -


this question has answer here:

i have list of tuples elements this:

aa = [('a', 'b'), ('c', 'd'), ('b', 'a')]

i want treat ('a', 'b') , ('b', 'a') same group , want extract unique tuples. output should this:

[('a', 'b'), ('c', 'd')]

how can achieve efficiently list consists of millions of such tuples?

convert frozenset, hash, , retrieve:

in [193]: map(tuple, set(map(frozenset, aa))) # python2 out[193]: [('d', 'c'), ('a', 'b')]

here's more readable version list comprehension:

in [194]: [tuple(x) x in set(map(frozenset, aa))] out[194]: [('d', 'c'), ('a', 'b')]

do note that, particular use case, list of tuples isn't best choice of data structure. consider storing data set begin with? 

in [477]: set(map(frozenset, aa)) out[477]: {frozenset({'a', 'b'}), frozenset({'c', 'd'})}

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