| Hash-Slice documentation | Contained in the Hash-Slice distribution. |
Hash::Slice - Make a hash from a deep slice of another hash
Version 0.03
use Hash::Slice qw/slice cslice/;
# A trivial example
my %hash = (a => 1, b => 2, c => 3);
my $slice = slice \%hash, qw/a b/;
# $slice is now { a => 1, b => 2 }
# A hairy example
my %hash = (a => 1, b => 2, c => { d => 3, e => 4 });
my $slice = slice \%hash, qw/a/, [ c => qw/e/ ];
# $slice is now { a => 1, c => { e => 4 } }
# An even hairier example
my %hash = (a => 1, b => 2, c => { d => 3, e => 4, f => { g => 5, h => 6, k => [ 0 .. 4 ] } }, z => 7);
my $slice = slice \%hash, qw/a z/, [ c => qw/e/, [ f => qw/g k/ ] ];
# $slice is now { a => 1, z => 7, c => { e => 4, f => { g => 5, k => [ 0, 1, 2, 3, 4 ] } } }
# Make a cloned-slice of %hash
my %hash = (a => 1, b => 2, c => { d => 3, e => 4, f => { g => 5, h => 6, k => [ 0 .. 4 ] } }, z => 7);
my $slice = cslice \%hash, qw/a z/, [ c => qw/e/, [ f => qw/g k/ ] ];
$slice->{c}->{e} = "red"; # $hash{c}->{e} is still 4
Hash::Slice lets you easily make a deep slice of a hash, specifically a hash containing one or more nested hashes. Instead of just taking a slice of the first level of a hash in an all-or-nothing manner, you can use slice to take a slice of the first level, then take a particular slice of the second level, and so on.
Make a copy of $hash according to @cut.
For each key in @cut, slice will copy the value of the key over to $slice->{$key}. If $slice encounters an ARRAY instead of a key, it will make a deep slice using the first element of ARRAY as the key and the rest of the array as the cut.
Note, this method will not make an entry in $slice unless the key exists in $hash
Note, unless you are making a deep cut, slice will simply copy the reference of the data being copied, and not make a clone. If you need to make a completely independent copy, use cslice or dcslice.
Make a copy of $hash according to @cut. $slice is an independent clone of $hash made using Clone::clone
Make a copy of $hash according to @cut. $slice is an independent clone of $hash made using Storable::dclone
Robert Krimen, <rkrimen at cpan.org>
You can contribute or fork this project via GitHub:
http://github.com/robertkrimen/hash-slice/tree/master
git clone git://github.com/robertkrimen/hash-slice.git Hash-Slice
Please report any bugs or feature requests to
bug-hash-slice at rt.cpan.org, or through the web interface at
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-Slice.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.
You can find documentation for this module with the perldoc command.
perldoc Hash::Slice
You can also look for information at:
Copyright 2007 Robert Krimen, all rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| Hash-Slice documentation | Contained in the Hash-Slice distribution. |
package Hash::Slice; use warnings; use strict;
our $VERSION = '0.03';
use vars qw/@ISA @EXPORT_OK/; @ISA = qw/Exporter/; @EXPORT_OK = qw/slice clone_slice cslice dclone_slice dcslice/; use Carp::Clan;
sub slice($@); sub slice($@) { my $hash = shift; my @cut = @_; my %slice; for my $name (@cut) { if (ref $name eq "ARRAY") { my ($name, @cut) = @$name; $slice{$name} = slice $hash->{$name}, @cut if exists $hash->{$name}; } elsif (ref $name eq "HASH") { croak "Can't use a HASH ($name) in a slice() \@cut"; while (my ($name, $cut) = each %$name) { $slice{$name} = slice $hash->{$name}, $cut if exists $hash->{$name}; } } else { $slice{$name} = $hash->{$name} if exists $hash->{$name}; } } return wantarray ? %slice : \%slice; }
sub clone_slice($@) { my $hash = shift; my @cut = @_; require Clone; my $clone_hash = Clone::clone($hash); return slice $clone_hash, @cut; } *cslice = \&clone_slice;
sub dclone_slice($@) { my $hash = shift; my @cut = @_; require Storable; my $dclone_hash = Storable::dclone($hash); return slice $dclone_hash, @cut; } *dcslice = \&dclone_slice;
1; # End of Hash::Slice