#!/usr/local/bin/perl
use strict;
use warnings;
use Data::Dumper;    
print Dumper \%ENV;

my %my_profile = (
    name => "Kahori",
    age  => 35,
    food  => "egg",
);
print "my name is $my_profile{name}\n";
print "my age is $my_profile{age}\n";
print "my food is $my_profile{food}\n\n";

my @keys = keys %my_profile;
print "@keys\n";
delete $my_profile{food};
if (exists $my_profile{age}){
print  "Age is not exist.\n"
}