Function Reference
— Built-in Function: subsref (val, idx)

Perform the subscripted element selection operation according to the subscript specified by idx.

The subscript idx is expected to be a structure array with fields ‘type’ and ‘subs’. Valid values for ‘type’ are ‘"()"’, ‘"{}"’, and ‘"."’. The ‘subs’ field may be either ‘":"’ or a cell array of index values.

The following example shows how to extract the two first columns of a matrix

          val = magic(3)
               val = [ 8   1   6
                         3   5   7
                         4   9   2 ]
          idx.type = "()";
          idx.subs = {":", 1:2};
          subsref(val, idx)
               [ 8   1
                   3   5
                   4   9 ]

Note that this is the same as writing val(:,1:2).

See also: subsasgn substruct