use strict;
use warnings;

my %hash = (
   list1 => ["foo", "bar", "baz"]

);


print "list1: [- ", join(" :: ", @{ $hash{list1} || []}), " -]\n";
print "list2: [- ", join(" :: ", @{ $hash{list2} || []}), " -]\n";

__END__
list1: [- foo :: bar :: baz -]
list2: [-  -]