intersect package:base-prelude

intersect :: Eq a => [a] -> [a] -> [a]
base-prelude BasePrelude
The intersect function takes the list intersection of two lists. For example, 
>>> [1,2,3,4] `intersect` [2,4,6,8]
[2,4]
If the first list contains duplicates, so will the result. 
>>> [1,2,2,3,4] `intersect` [6,4,4,2]
[2,2,4]
It is a special case of intersectBy, which allows the programmer to supply their own equality test. If the element is found in both the first and the second list, the element from the first list will be used.
intersectBy :: (a -> a -> Bool) -> [a] -> [a] -> [a]
base-prelude BasePrelude
The intersectBy function is the non-overloaded version of intersect.