if (grep { $bands[0] eq $_ } qw(red green blue yellow))

##</code><code>##

use List::MoreUtils qw(any);
if (any { $bands[0] eq $_ } qw(red green blue yellow))

##</code><code>##

my %colors = map { $_ => 1 } qw(red green blue yellow);
if (exists $colors{$bands[0]})