1Hash::MoreUtils(3)    User Contributed Perl Documentation   Hash::MoreUtils(3)
2
3
4

NAME

6       Hash::MoreUtils - Provide the stuff missing in Hash::Util
7

SYNOPSIS

9         use Hash::MoreUtils qw(slice slice_def slice_exists slice_grep
10                                hashsort
11                               );
12

DESCRIPTION

14       Similar to "List::MoreUtils", "Hash::MoreUtils" contains trivial but
15       commonly-used functionality for hashes.
16

FUNCTIONS

18   "slice" HASHREF[, LIST]
19       Returns a hash containing the (key, value) pair for every key in LIST.
20
21   "slice_def" HASHREF[, LIST]
22       As "slice", but only includes keys whose values are defined.
23
24   "slice_exists" HASHREF[, LIST]
25       As "slice" but only includes keys which exist in the hashref.
26
27   "slice_grep" BLOCK, HASHREF[, LIST]
28       As "slice", with an arbitrary condition.
29
30       Unlike "grep", the condition is not given aliases to elements of
31       anything.  Instead, %_ is set to the contents of the hashref, to avoid
32       accidentally auto-vivifying when checking keys or values.  Also,
33       'uninitialized' warnings are turned off in the enclosing scope.
34
35   "hashsort" [BLOCK,] HASHREF
36         my @array_of_pairs  = hashsort \%hash;
37         my @pairs_by_length = hashsort sub { length($a) <=> length($b) }, \%hash;
38
39       Returns the (key, value) pairs of the hash, sorted by some property of
40       the keys.  By default (if no sort block given), sorts the keys with
41       "cmp".
42
43       I'm not convinced this is useful yet.  If you can think of some way it
44       could be more so, please let me know.
45
46   "safe_reverse" [BLOCK,] HASHREF
47         my %dup_rev = safe_reverse \%hash
48
49         sub croak_dup {
50             my ($k, $v, $r) = @_;
51             exists( $r->{$v} ) and
52               croak "Cannot safe reverse: $v would be mapped to both $k and $r->{$v}";
53             $v;
54         };
55         my %easy_rev = save_reverse \&croak_dup, \%hash
56
57       Returns safely reversed hash (value, key pairs of original hash). If no
58       "BLOCK" is given, following routine will be used:
59
60         sub merge_dup {
61             my ($k, $v, $r) = @_;
62             return exists( $r->{$v} )
63                    ? ( ref($r->{$v}) ? [ @{$r->{$v}}, $k ] : [ $r->{$v}, $k ] )
64                    : $k;
65         };
66
67       The "BLOCK" will be called with 3 arguments:
68
69       "key"   The key from the "( key, value )" pair in the original hash
70
71       "value" The value from the "( key, value )" pair in the original hash
72
73       "ref-hash"
74               Reference to the reversed hash (read-only)
75
76       The "BLOCK" is expected to return the value which will used for the
77       resulting hash.
78

AUTHOR

80       Hans Dieter Pearcey, "<hdp@cpan.org>" Jens Rehsack,
81       "<rehsack@cpan.org>"
82

BUGS

84       Please report any bugs or feature requests to
85       "bug-hash-moreutils@rt.cpan.org", or through the web interface at
86       http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-MoreUtils
87       <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-MoreUtils>.  I
88       will be notified, and then you'll automatically be notified of progress
89       on your bug as I make changes.
90

SUPPORT

92       You can find documentation for this module with the perldoc command.
93
94           perldoc Hash::MoreUtils
95
96       You can also look for information at:
97
98       ·   RT: CPAN's request tracker
99
100           http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-MoreUtils
101           <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-MoreUtils>
102
103       ·   AnnoCPAN: Annotated CPAN documentation
104
105           http://annocpan.org/dist/Hash-MoreUtils
106           <http://annocpan.org/dist/Hash-MoreUtils>
107
108       ·   CPAN Ratings
109
110           http://cpanratings.perl.org/d/Hash-MoreUtils
111           <http://cpanratings.perl.org/d/Hash-MoreUtils>
112
113       ·   Search CPAN
114
115           http://search.cpan.org/dist/Hash-MoreUtils/
116           <http://search.cpan.org/dist/Hash-MoreUtils/>
117

ACKNOWLEDGEMENTS

120       Copyright 2005 Hans Dieter Pearcey, all rights reserved.  Copyright
121       2010 Jens Rehsack
122
123       This program is free software; you can redistribute it and/or modify it
124       under the terms of either: the GNU General Public License as published
125       by the Free Software Foundation; or the Artistic License.
126
127       See http://dev.perl.org/licenses/ for more information.
128
129
130
131perl v5.12.3                      2011-03-14                Hash::MoreUtils(3)



        

    


            
        

        

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