ArrayReduce

ArrayReduce[f, array, n] reduces dimension n of array by applying f.

ArrayReduce[f, array, n1;;n2] reduces dimensions n1 through n2.

ArrayReduce[f, array, {n1, n2, ...}] reduces dimensions n1, n2, etc.

Examples

Sum over the first dimension:

ArrayReduce[Total, {{1, 2}, {3, 4}}, 1]
(* {4, 6} *)

Reduce multiple dimensions:

ArrayReduce[Max, RandomReal[1, {3, 4, 5}], {1, 2}]

Please visit the official Wolfram Language Reference for more details.