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 (2026-02-20 12:42:29 GIT hash dbcc3e4b3d2a59f66230b482cff8f0b018178d77 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)}