Hashable Data Structure With No Order And Allowed Duplicates

I have list of tuples/lists (-1, 0, 1) (-1, 1, 0) (-1, 2, -1) (-1, -1, 2) (0, 1, -1) I need them to be : (-1, 1, 0) (-1, 2, -1) I want (-1, 0, 1) and (-1, 1, 0) map to the same thi

Solution 1:

You could sort the tuples and use set to check for duplicates as tuples are hashable

a=[(-1, 0, 1) ,(-1, 1, 0), (-1, 2, -1) ,(-1, -1, 2), (0, 1, -1)]
my_set=set()
res=[]
for original_value, sorted_value inzip(a,map(sorted,a)):
    iftuple(sorted_value) notin my_set:
        res.append(original_value)
        my_set.add(tuple(sorted_value))

Output

[(-1, 0, 1), (-1, 2, -1)]

Can use defaultdict

from collections import defaultdict
d=defaultdict(list)
a=[(-1, 0, 1) ,(-1, 1, 0), (-1, 2, -1) ,(-1, -1, 2), (0, 1, -1)]

res=[]
for original_value, sorted_value inzip(a,map(sorted,a)):
    d[tuple(sorted_value)].append(original_value)

Output:

{
(-1, -1, 2): [(-1, 2, -1), (-1, -1, 2)], 
(-1, 0, 1): [(-1, 0, 1), (-1, 1, 0), (0, 1, -1)]
}

Solution 2:

You can use collections.Counter to efficiently take the signatures of each tuple in your list, map the items of the Counter objects to frozensets so the signatures become hashable, put them in a set to de-duplicate, and then re-create the tuples using the Counter.elements() method:

from collections import Counter
l = [(-1, 0, 1), (-1, 1, 0), (-1, 2, -1), (-1, -1, 2), (0, 1, -1)]
[tuple(Counter(dict(i)).elements()) for i in {frozenset(Counter(t).items()) for t in l}]

This returns:

[(0, -1, 1), (-1, -1, 2)]

Solution 3:

You can use set to avoid adding elements that map to the same thing.

l = [(-1, 0, 1), (-1, 1, 0), (-1, 2, -1), (-1, -1, 2), (0, 1, -1)]

new_l = []

for i in l:
    ifset(i) not in [set(j) for j in new_l]:
        new_l += [i]

print new_l

It returns [(-1, 0, 1), (-1, 2, -1)]

Edit

This incorrectly flags some tuples as duplicates. This should work :

l = [(-1, 0, 1), (-1, 1, 0), (-1, 2, -1), (-1, -1, 2), (0, 1, -1)]

new_l = list(set([tuple(sorted(i)) for i in l]))

print new_l