group_map_reduce
Sequence.group_map_reduce
(K
type
:
property.orderable, B type
, key_f Unary K T, f Unary B T, reduce_f Binary B B B) =>
container.Map K B¶Type Parameters
type of the keys
0.095dev (2025-09-09 14:29:31 GIT hash 98644f8f651c2101a0730cfe31c5807993b7603b built by fridi@fzen)
reduce elements within a group by first applying f and then using reduce_f to reduce
example: count occurrences of letters, numbers and other characters
=> {(digit => 2), (letter => 3), (other => 1)}