my @hiddenKeys = qq(@cityKeys @distanceKeys);

##</code><code>##

my @hiddenKeys = (@cityKeys, @distanceKeys);

##</code><code>##

use Data::Dumper;
my @a = (1,2);

my @b = (3,4);
my @c = qq(@a @b);
print Dumper(\@a);
print Dumper(\@b);
print Dumper(\@c);