SYNOPSIS

use Hash::MoreUtils qw(slice slice_def slice_exists slice_grep
hashsort
);

DESCRIPTION

FUNCTIONS

slice HASHREF[, LIST]

If no "LIST" is given, all keys are assumed as "LIST".

slice_def HASHREF[, LIST]

If no "LIST" is given, all keys are assumed as "LIST".

slice_exists HASHREF[, LIST]

If no "LIST" is given, all keys are assumed as "LIST".

slice_grep BLOCK, HASHREF[, LIST]

If no "LIST" is given, all keys are assumed as "LIST".

Unlike "grep", the condition is not given aliases to elements of anything. Instead, %_ is set to the contents of the hashref, to avoid accidentally auto-vivifying when checking keys or values. Also, 'uninitialized' warnings are turned off in the enclosing scope.

slice_map HASHREF[, MAP]

If no "MAP" is given, all keys of "HASHREF" are assumed mapped to theirself.

slice_def_map HASHREF[, MAP]

If no "MAP" is given, all keys of "HASHREF" are assumed mapped to theirself.

slice_exists_map HASHREF[, MAP]

If no "MAP" is given, all keys of "HASHREF" are assumed mapped to theirself.

slice_grep_map BLOCK, HASHREF[, MAP]

If no "MAP" is given, all keys of "HASHREF" are assumed mapped to theirself.

Unlike "grep", the condition is not given aliases to elements of anything. Instead, %_ is set to the contents of the hashref, to avoid accidentally auto-vivifying when checking keys or values. Also, 'uninitialized' warnings are turned off in the enclosing scope.

hashsort [BLOCK,] HASHREF

  my @array_of_pairs  = hashsort \%hash;
  my @pairs_by_length = hashsort sub { length($a) <=> length($b) }, \%hash;

Returns the (key, value) pairs of the hash, sorted by some property of the keys. By default (if no sort block given), sorts the keys with "cmp".

I'm not convinced this is useful yet. If you can think of some way it could be more so, please let me know.

safe_reverse [BLOCK,] HASHREF

  my %dup_rev = safe_reverse \%hash
  sub croak_dup {
      my ($k, $v, $r) = @_;
      exists( $r->{$v} ) and
        croak "Cannot safe reverse: $v would be mapped to both $k and $r->{$v}";
      $v;
  };
  my %easy_rev = save_reverse \&croak_dup, \%hash

Returns safely reversed hash (value, key pairs of original hash). If no "BLOCK" is given, following routine will be used:

  sub merge_dup {
      my ($k, $v, $r) = @_;
      return exists( $r->{$v} )
             ? ( ref($r->{$v}) ? [ @{$r->{$v}}, $k ] : [ $r->{$v}, $k ] )
             : $k;
  };

The "BLOCK" will be called with 3 arguments:

"key"

The key from the "( key, value )" pair in the original hash

"value"

The value from the "( key, value )" pair in the original hash

"ref-hash"

Reference to the reversed hash (read-only)

The "BLOCK" is expected to return the value which will used for the resulting hash.

AUTHOR

SUPPORT

    perldoc Hash::MoreUtils

You can also look for information at:

• RT: CPAN's request tracker

  <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-MoreUtils>

• AnnoCPAN: Annotated CPAN documentation

  <http://annocpan.org/dist/Hash-MoreUtils>

• CPAN Ratings

  <http://cpanratings.perl.org/d/Hash-MoreUtils>

• Search CPAN

  <http://search.cpan.org/dist/Hash-MoreUtils/>

ACKNOWLEDGEMENTS

COPYRIGHT & LICENSE

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.