How to find if an element of a list is in another list?

Question

I want to know if at least one element in a first list can be found in a second list.

I can see two ways to do it. Let\'s say our lists are:

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Answer 1

The second one has better performance on large lists than the first one. Intersect puts the elements of one list into a hash table before checking the other list's elements for membership.