Tie::Hash::MultiValueOrdered(3pm) User Contributed Perl Documentation Tie::Hash::MultiValueOrdered(3pm)

Tie::Hash::MultiValueOrdered - hash with multiple values per key, and ordered keys

   use Test::More;
   use Tie::Hash::MultiValueOrdered;
   
   my $tied = tie my %hash, "Tie::Hash::MultiValueOrdered";
   
   $hash{a} = 1;
   $hash{b} = 2;
   $hash{a} = 3;
   $hash{b} = 4;
   
   # Order of keys is predictable
   is_deeply(
      [ keys %hash ],
      [ qw( a b ) ],
   );
   
   # Order of values is predictable
   # Note that the last values of 'a' and 'b' are returned.
   is_deeply(
      [ values %hash ],
      [ qw( 3 4 ) ],
   );
   
   # Can retrieve list of all key-value pairs
   is_deeply(
      [ $tied->pairs ],
      [ qw( a 1 b 2 a 3 b 4 ) ],
   );
   
   # Switch the retrieval mode for the hash.
   $tied->fetch_first;
   
   # Now the first values of 'a' and 'b' are returned.
   is_deeply(
      [ values %hash ],
      [ qw( 1 2 ) ],
   );
   
   # Switch the retrieval mode for the hash.
   $tied->fetch_list;
   
   # Now arrayrefs are returned.
   is_deeply(
      [ values %hash ],
      [ [1,3], [2,4] ],
   );
   
   # Restore the default retrieval mode for the hash.
   $tied->fetch_last;
   
   done_testing;

A hash tied to this class acts more or less like a standard hash, except that when you assign a new value to an existing key, the old value is retained underneath. An explicit "delete" deletes all values associated with a key.

By default, the old values are inaccessible through the hash interface, but can be retrieved via the tied object:

   my @values = tied(%hash)->get($key);

However, the "fetch_*" methods provide a means to alter the behaviour of the hash.

"pairs"
Returns all the hash's key-value pairs (including duplicates) as a flattened list.
"pair_refs"
Returns all the hash's key-value pairs (including duplicates) as a list of two item arrayrefs.
"get($key)"
Returns the list of all values associated with a key.
"keys"
The list of all hash keys in their original order. Where a key is duplicated, only the first occurrence is returned.
"rr_keys"
The list of all hash keys in their original order. Where a key is duplicated, only the last occurrence is returned.
"all_keys"
The list of all hash keys in their original order, including duplicates.
"values"
The values corresponding to "keys".
"rr_values"
The values corresponding to "rr_keys".
"all_values"
The values corresponding to "all_keys".

"fetch_last"
This is the default style of fetching. 

   tie my %hash, "Tie::Hash::MultiValueOrdered";
   
   $hash{a} = 1;
   $hash{b} = 2;
   $hash{b} = 3;
   
   tied(%hash)->fetch_last;
   
   is($hash{a}, 1);
   is($hash{b}, 3);
"fetch_first"
   tie my %hash, "Tie::Hash::MultiValueOrdered";
   
   $hash{a} = 1;
   $hash{b} = 2;
   $hash{b} = 3;
   
   tied(%hash)->fetch_first;
   
   is($hash{a}, 1);
   is($hash{b}, 2);
"fetch_list"
   tie my %hash, "Tie::Hash::MultiValueOrdered";
   
   $hash{a} = 1;
   $hash{b} = 2;
   $hash{b} = 3;
   
   tied(%hash)->fetch_first;
   
   is_deeply($hash{a}, [1]);
   is_deeply($hash{b}, [2, 3]);
"fetch_iterator"
This fetch style is experimental and subject to change. 

   tie my %hash, "Tie::Hash::MultiValueOrdered";
   
   $hash{a} = 1;
   $hash{b} = 2;
   $hash{b} = 3;
   
   tied(%hash)->fetch_iterator;
   
   my $A = $hash{a};
   my $B = $hash{b};
   
   is($A->(), 1);
   is($B->(), 2);
   is($B->(), 3);

Please report any bugs to <http://rt.cpan.org/Dist/Display.html?Queue=JSON-MultiValueOrdered>.

JSON::Tiny::Subclassable, JSON::Tiny, Mojo::JSON.

Toby Inkster <tobyink@cpan.org>.

This software is copyright (c) 2012-2013 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

2022-11-20 perl v5.36.0