#e.g.
lemon-lemon
apple-orange
orange-lemon
orange-apple

##</code><code>##

my %hash = map { $keys[$_] => $values[$_] } 0.. $#keys;

for (my $i=0; $i<@apple_ids; $i++)  {
        while ( my ($key, $value) = each(%hash) ) {

                if ($apple_ids[$i] == $key) {
                        print "apple";
                }
                if ($apple_ids[$i] == $value)     {
                        print "apple";
                }
        }
}

for (my $i=0; $i<@orange_ids; $i++)  {
        while ( my ($key, $value) = each(%hash) ) {

                if ($orange_ids[$i] == $key) {
                        print "orange";
                }
                if ($orange_ids[$i] == $value)     {
                        print "orange";
                }
        }
}
for (my $i=0; $i<@lemon_ids; $i++)  {
        while ( my ($key, $value) = each(%hash) ) {

                if ($lemon_ids[$i] == $key) {
                        print "lemon";
                }
                if ($lemon_ids[$i] == $value)     {
                        print "lemon";
                }
        }
}