in reply to Having a problem creating a hash with the map function

If you wanted to get fancy and cryptic, you could create your "goal" hash by: 
    my %Belfast_car_dealer_hash =  map{$_=>1} 
                 @{$car_city_dealer_aoa[0]} [1..$#{$car_city_dealer_ao
+a[0]}];

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but I would not write code like that without an explanation:
It uses an array-slice of @{ $car_city_dealer_aoa[0] }, skipping the first (0) element, and mapping the rest.

             "By three methods we may learn wisdom: First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest."           -Confucius

In Section Seekers of Perl Wisdom