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Clone - recursively copy Perl datatypes

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    use Clone 'clone';

    my $data = {
       set => [ 1 .. 50 ],
       foo => {
           answer => 42,
           object => SomeObject->new,

    my $cloned_data = clone($data);

    $cloned_data->{foo}{answer} = 1;
    print $cloned_data->{foo}{answer};  # '1'
    print $data->{foo}{answer};         # '42'

You can also add it to your class:

    package Foo;
    use parent 'Clone';
    sub new { bless {}, shift }

    package main;

    my $obj = Foo->new;
    my $copy = $obj->clone;


This module provides a clone() method which makes recursive copies of nested hash, array, scalar and reference types, including tied variables and objects.

clone() takes a scalar argument and duplicates it. To duplicate lists, arrays or hashes, pass them in by reference, e.g.

    my $copy = clone (\@array);

    # or

    my %copy = %{ clone (\%hash) };


Storable's dclone() is a flexible solution for cloning variables, albeit slower for average-sized data structures. Simple and naive benchmarks show that Clone is faster for data structures with 3 or fewer levels, while dclone() can be faster for structures 4 or more levels deep.


Copyright 2001-2022 Ray Finch. All Rights Reserved.

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


Ray Finch <>

Breno G. de Oliveira <>, Nicolas Rochelemagne <> and Florian Ragwitz <> perform routine maintenance releases since 2012.