my @match_to_array = (a,b,c,a,d,c,b,r);
my %seen = ();
my @r = ();

foreach my $a (@match_to_array) {
    unless ($seen{$a}) {
        push @r, $a;
        $seen{$a}++;
    }
}
print "@r";
print "\n@match_to_array";