foreach my $k1 ( keys %{ $hash{'prefix'} } ) {
     for my $k2 ( keys %{ $hash{$k1} } ) {
          print("$k2\n");
     }
}
[download]

As someone said, you can't just make stuff up and expect the computer to know what you want. :-)

Slow down. Have another look at the links you've been given and use plenty of Data::Dumper at every step. Good luck!

#!/usr/local/bin/perl

use strict;
use warnings;

use Data::Dumper;
$Data::Dumper::Indent = 1;
$Data::Dumper::Sortkeys = 1;

my %hash = (
  'summary' => {
    'allotments' => 679
  },
  'prefix' => {
    '32 ' => 425,
    '45 ' => 5,
    '41 ' => 2,
    '46 ' => 5,
    '44 ' => 1,
    '47 ' => 9,
    '43 ' => 1,
    '27 ' => 1,
    '48 ' => 212,
    '22 ' => 14,
    '29 ' => 2,
    '40 ' => 2
  },
);

for my $key (keys %hash){
  print qq{key: $key\n};
  for my $subkey (keys %{$hash{$key}}){
    print qq{\tsubkey: $subkey\n};
  }
}
[download]

outputs

key: summary
    subkey: allotments
key: prefix
    subkey: 32 
    subkey: 45 
    subkey: 41 
    subkey: 44 
    subkey: 46 
    subkey: 47 
    subkey: 27 
    subkey: 43 
    subkey: 48 
    subkey: 29 
    subkey: 22 
    subkey: 40
[download]

As someone said, you can't just make stuff up and expect the computer to know what you want

It was dominus in comp.lang.perl.misc, but he was a little more cruel than you. Read more of his pearls of wisdom if you want a laugh. Contains many naughty words and traces of nut. Beware.