elemIndex -package:vector-sized -package:vector -package:numeric-prelude package:storablevector

O(n) The elemIndex function returns the index of the first element in the given Vector which is equal to the query element, or Nothing if there is no such element.

O(n) The elemIndexEnd function returns the last index of the element in the given Vector which is equal to the query element, or Nothing if there is no such element. The following holds:

elemIndexEnd c xs ==
(-) (length xs - 1) `fmap` elemIndex c (reverse xs)