group package:base-prelude

group :: Eq a => [a] -> [[a]]
base-prelude BasePrelude
The group function takes a list and returns a list of lists such that the concatenation of the result is equal to the argument. Moreover, each sublist in the result contains only equal elements. For example, 
>>> group "Mississippi"
["M","i","ss","i","ss","i","pp","i"]
It is a special case of groupBy, which allows the programmer to supply their own equality test.
groupBy :: (a -> a -> Bool) -> [a] -> [[a]]
base-prelude BasePrelude
The groupBy function is the non-overloaded version of group.
groupWith :: Ord b => (a -> b) -> [a] -> [[a]]
base-prelude BasePrelude
The groupWith function uses the user supplied function which projects an element out of every list element in order to first sort the input list and then to form groups by equality on these projected elements
class Semigroup a
base-prelude BasePrelude
The class of semigroups (types with an associative binary operation). Instances should satisfy the following:
  • Associativity x <> (y <> z) = (x <> y) <> z