mylist = [[1,2],[4,5],[3,4],[4,3],[2,1],[1,2]]
I want to remove duplicate items, duplicated items can be reversed. The result should be :
mylist = [[1,2],[4,5],[3,4]]
How do I achieve this in Python?
3 Answers
lst=[[1,2],[4,5],[3,4],[4,3],[2,1],[1,2]]
fset = set(frozenset(x) for x in lst)
lst = [list(x) for x in fset]
This won't preserve order from your original list, nor will it preserve order of your sublists.
>>> lst=[[1,2],[4,5],[3,4],[4,3],[2,1],[1,2]]
>>> fset = set(frozenset(x) for x in lst)
>>> lst = [list(x) for x in fset]
>>> lst
[[1, 2], [3, 4], [4, 5]]
2 Comments
Oleg
Not exactly, assume you have
[0,0] in your lst, this will be collapsed to [0].
mgilson
That's true. If you're gauranteed that the inputs always have only 2 items and you want to preserve that in the output, it's pretty easy to post-process to turn the 1-element lists into 2-element lists :)
If the Order Matters you can always use OrderedDict
>>> unq_lst = OrderedDict()
>>> for e in lst:
unq_lst.setdefault(frozenset(e),[]).append(e)
>>> map(list, unq_lst.keys())
[[1, 2], [4, 5], [3, 4]]
Comments
If order is not important:
def rem_dup(l: List[List[Any]]) -> List[List[Any]]:
tuples = map(lambda t: tuple(sorted(t)), l)
return [list(t) for t in set(tuples)]
listas a variable name.