Prepend

Prepend[expr, elem] gives expr with elem prepended.

Examples

Prepend to a list:

Prepend[{b, c, d}, a]
(* {a, b, c, d} *)

Operator form:

Prepend[x][{1, 2, 3}]
(* {x, 1, 2, 3} *)

Please visit the official Wolfram Language Reference for more details.