find package:mono-traversable

find takes a predicate and a sequence and returns the first element in the sequence matching the predicate, or Nothing if there isn't an element that matches the predicate.
> find (== 5) [1 .. 10]
Just 5

> find (== 15) [1 .. 10]
Nothing
Like lookup, but uses a default value when the key does not exist in the map.
Use Data.List's implementation of find.