@a = map {
    $_->[0]
} sort {
    $a->[1] <=> $b->[1]
    ||
    $a->[ 2 ] cmp $b->[ 2 ]
} map {
    [ $_, COMPLEX EXPRESSION ]
} @b;

##</code><code>##

@a = map{
    substr $_, 16
} sort map {
    m[...(\d+)...( \d+.\d+)...([a-z]4)...] or die "Illformed data '$_'";
    pack 'A4dNA*', $3, $2, $1, $_
} @b;