Relude.Extra.Group

Polymorphic grouping functions.

Documentation

groupBy :: forall f t a. (Foldable f, DynamicMap t, Val t ~ NonEmpty a, Monoid t) => (a -> Key t) -> f a -> t

Groups elements using results of the given function as keys.

>>> groupBy even [1..6] :: HashMap Bool (NonEmpty Int)
fromList [(False,5 :| [3,1]),(True,6 :| [4,2])]

groupOneBy :: forall f t a. (Foldable f, DynamicMap t, Val t ~ a, Monoid t) => (a -> Key t) -> f a -> t

Similar to groupBy but keeps only one element as value.

>>> groupOneBy even [1 .. 6] :: HashMap Bool Int
fromList [(False,1),(True,2)]