use strict;
use warnings;
use Data::Dumper;
use Data::Dump::Streamer;

my %hash = (
     this => ['one', 2, 3.1],
     that => undef,
     );

print Dumper (\%hash);
Dump (\%hash);

##</code><code>##

$VAR1 = {
          'that' => undef,
          'this' => [
                      'one',
                      2,
                      '3.1'
                    ]
        };
$HASH1 = {
           that => undef,
           this => [
                     'one',
                     2,
                     3.1
                   ]
         };