lars_woetmann wrote:
> I have a list I filter using another list and I would like this to be
> as fast as possible right now I do like this:
>
> [x for x in list1 if x not in list2]
>
> i tried using the method filter:
>
> filter(lambda x: x not in list2, list1)
>
> but it didn't make much difference, because of lambda I guess
> is there any way I can speed this up
if list2 is a list object, "not in list2" is an O(N) operation.
maybe you should use sets instead ? does the following work
better ?
set2 = set(list2)
result = [x for x in list1 if x not in set2]
?
</F>
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