my %index = (firstname => 0,
             lastname  => 1,
             address   => 2,
             town      => 3,
             zip       => 4);

my @array1 = ("Bob", "Smith", "1234 Main St", "Anytown", "20500");
my @array2 = ("Joe", "Blow", "4321 Street Ln", "Notown", "20050");

print "First name (from array1): $array1[ $index{firstname} ]\n";
print "Address    (from array2): $array2[ $index{address}   ]\n";

##</code><code>##

use constant { FIRSTNAME => 0,
               LASTNAME  => 1,
               ADDRESS   => 2,
               TOWN      => 3,
               ZIP       => 4 };

my @array1 = ("Bob", "Smith", "1234 Main St", "Anytown", "20500");
my @array2 = ("Joe", "Blow", "4321 Street Ln", "Notown", "20050");

print "First name (from array1): $array1[ FIRSTNAME ]\n";
print "Address    (from array2): $array2[ ADDRESS   ]\n";