:: Eq a => [a] -> a -> Bool -package:ghc -package:base-compat -package:calligraphy package:Agda
Check membership for the same list often. Use partially applied to
create membership predicate
hasElem xs :: a -> Bool.
- First time: O(n log n) in the worst case.
- Subsequently: O(log n).
Specification:
hasElem xs == (elem xs).
A generalised variant of elemIndex. O(n).