#!/usr/bin/perl

use strict;
use warnings;

use Perl6::Junction qw/none/;
use Data::Dumper;

my %colors = ( red => '#ff0000', blue => '#0000ff', 
               green => '#00ff00', yellow => '#ffff00', );

my @sel_col = qw/ red green /;

print Dumper [grep {none(@sel_col) eq $_} keys %colors];