my @array = qw( 2aa 2ba 12kf 9cn 9vn 21sg );
    my @idx= do {
        my @key = @array;
        s[(\d+)][ pack "N", $1 ]ge   for  @key;
        sort { $key[$a] cmp $key[$b] } 0..$#key;
    };
    my @sorted= @array[@idx];
    print "@sorted\n";