my @good = grep {
    my $yes = $_;
    !grep $_ == $yes, @notgood; 
} @goodarray;

##</code><code>##

my @good = grep {
    my $yes = $_;
    !first {$_ == $yes} @notgood;
} @goodarray;

##</code><code>##

my @good = grep { not @notgood ~~ $_ } @goodarray;