use strict;
use warnings;

$\ = "\n";
$, = ', ';


my %hash = ();
$hash{"h"} = 10;
$hash{"z"} = 20;
$hash{"a"} = 30;

foreach my $key (keys %hash) {
    print "$key: $hash{$key}";
}

--output:--
a: 30
h: 10
z: 20