in reply to Re^2: meaning for the hash code
in thread meaning for the hash code

Hi Tony, I'll try to explain a little more what the code does step by step:

  1. First, we store several hash values in a var called ages,

    use Tie::Hash::Sorted; my %ages = ( 'John' => 33, 'Jacob' => 29, 'Jingle' => 15, 'Heimer' => 48, 'Smitz' => 12, );

    Then we will have those values: $ages{'John'}=33, $ages{'Jacob'}=29, and so on...

  2. At this point we define a subroutine, that will be assigned through a variable name ($sort_by_numeric_value) later to the module itself.

    Nothing is still done because we didn't pass a hash to it, we'll do it later. I have checked Tie::Hash::Sorted and it looks like you can use your own personal sorting subroutine too if you want.

    my $sort_by_numeric_value = sub { my $hash = shift; sort {$hash->{$b} <=> $hash->{$a}} keys %$hash ; };

    (Normally the subs should be better at the bottom of the code, but I suppose that it's declared there for educational purposes).

    The subroutine will "shift" every value listed on the hash we will pass, sorting them accordingly.

  3. At this time we will use a new variable (%sorted_ages) to store the sorted list of 'unsorted' hashes stored in %ages.

    Through Tie::Hash::Sorted we specify which hash we want to sort (%hash) and with which method we will sort the values ($sort_by _numeric_value, the subroutine we defined just before).

    tie my %sorted_ages, 'Tie::Hash::Sorted', 'Hash' => \ %ages, 'Sort_Routine' => $sort_by_numeric_value;
  4. At last, we return the sorted list of values by the standard output (our screen, normally ;-)). Check that $name belongs to the 'keys' stored in %sorted_ages (John, Jacob...) and that $sorted_ages{$name} stores the value belonging to each key (33,29,...).

    for my $name ( keys %sorted_ages ) { print "$name is $sorted_ages{$name} years old.\n"; }

Hope it helps!