GAP Manual: 27.6. Add

Add( list, elm )

Add adds the element elm to the end of the list list, i.e., it is equivalent to the assignment list[ Length(list) + 1 ] := elm. The list is automatically enlarged to make room for the new element. Add returns nothing, it is called only for its side effect.

Note that adding to a list changes the list. The ability to change an object is only available for lists and records (see Identical Lists).

To add more than one element to a list use Append (see Append).

    gap> l := [ 2, 3, 5 ];;  Add( l, 7 );  l;
    [ 2, 3, 5, 7 ]