sub combine_rows
{
    my ( $label, @arrays ) = @_;

    my @joined;
    for my $i ( 0 .. $#{$arrays[0]} ) {  # assumes that all arrays are the same size
        push @joined, join( ';', $label, map { $arrays[$_][$i] } 0 .. $#arrays );
    }
    return \@joined;
}