use strict;
use warnings;

my @list;
$list[0] = 0;
$list[2] = 2;
@list = sort {$a <=> $b} @list;

##</code><code>##

use strict;
use warnings;

my @list;
$list[0] = [0];
$list[2] = [2];
@list = sort {$$a[0] <=> $$b[0]} @list;