FAQ 4.64 How can I get the unique keys from two hashes?

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Repair the corrupted file:

   perl -p -i -e 'tr/\r//d' bad_file

    Tad McClellan                          SGML consulting
    tadmc@augustmail.com                   Perl programming
    Fort Worth, Texas

Re: FAQ 4.64 How can I get the unique keys from two hashes?

This is an excerpt from the latest version perlfaq4.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .


4.64: How can I get the unique keys from two hashes?

    First you extract the keys from the hashes into lists, then solve the
    "removing duplicates" problem described above. For example:

            %seen = ();
            for $element (keys(%foo), keys(%bar)) {
            @uniq = keys %seen;

    Or more succinctly:

            @uniq = keys %};

    Or if you really want to save space:

            %seen = ();
            while (defined ($key = each %foo)) {
            while (defined ($key = each %bar)) {
            @uniq = keys %seen;


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