Like this

 sub Fompare {
   my( $pree, $post ) = @_;
   for my $item ( @{ $pree } ){
      print "$item\n";
      print "yes\n" if InIt( $item, $post );
   }
}
sub InIt {
   my( $item, $post ) = @_;
   for my $postItem ( @$post ){
      return !!1 if $item eq $postItem;
      return !!1 if $item == $postItem;
   }
}
[download]

But see references quick reference and grep