#!/usr/bin/perl

%hash = qw(first David last Sherrill);

$check_first = exists $hash{"first"};
$check_age = exists $hash{"age"};

# "false" doesn't show up as a 0 unless "forced"
$num = ( $check_age == 0 ) ? 0 : 1;

print "Does first exist? $check_first\n";
# Does first exist? 1

print "Does age exist? $check_age\n";
# Does age exist? 

print "variable num = $num\n";
# variable num = 0