FAQ 4.75 How do I print out or copy a recursive data structure?

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4.75: How do I print out or copy a recursive data structure?

    The "Data::Dumper" module on CPAN (or the 5.005 release of Perl) is
    great for printing out data structures. The "Storable" module on CPAN
    (or the 5.8 release of Perl), provides a function called "dclone" that
    recursively copies its argument.

            use Storable qw(dclone);
            $r2 = dclone($r1);

    Where $r1 can be a reference to any kind of data structure you'd like.
    It will be deeply copied. Because "dclone" takes and returns references,
    you'd have to add extra punctuation if you had a hash of arrays that you
    wanted to copy.

            %newhash = %{ dclone(\%oldhash) };


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