my @data = qw(1a 1b 2a 2b);
my @s1 = reverse sort { $a <=> $b } @data;
my @s2 = sort { $b <=> $a } @data;
print "@s1\n@s2\n";

##</code><code>##

2b 2a 1b 1a
2a 2b 1a 1b