BlockMap

BlockMap[f, list, n] applies f to non-overlapping sublists of length n in list.

BlockMap[f, list, n, d] applies f to sublists with offset d in list.

BlockMap[f, list, {n1, n2, ...}, ...] applies f to blocks of size n1×n2×....

Examples

Apply function to blocks of 2:

BlockMap[f, {a, b, c, d, e, f}, 2]
(* {f[{a, b}], f[{c, d}], f[{e, f}]} *)

Sum pairs:

BlockMap[Total, {1, 2, 3, 4, 5, 6}, 2]
(* {3, 7, 11} *)

Please visit the official Wolfram Language Reference for more details.