my @A = [ '1', '2', '4', '8' ];
my @B = [ '1', '3', '6', '8' ];

my @C;

foreach my $A (@A) { 
   foreach my $B (@B) {
   
   if ($A == $B) {
     push @C, $A;
   }
   // something here to take the elements out?
   }
}