@ar2 = @ar1[@sl]; 

##</code><code>##

$ar2[0] = $ar1[ $s1[0] ];
$ar2[1] = $ar1[ $s1[1] ];

##</code><code>##

$ar2[0] = $ar1[ 'b' ];
$ar2[1] = $ar1[ 'd' ];

##</code><code>##

    Argument "b" isn't numeric in array slice at /tmp/r line 10.
    Argument "d" isn't numeric in array slice at /tmp/r line 10.