use warnings;
use diagnostics;
use strict;

my @array = ("8.foo", "6.bar", "7.baz",
"5.biz", "3.fizzle", "0.fro", "9.boz");

print join "\n",
sort {by_number($a) <=> by_number($b)} @array;

sub by_number {
        my $value = shift;
        if ($value =~ m/^(\d+)/) {
                return $1
        }
}