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copied!<h2>Quick Answer (TL;DR)</h2> <pre> %hash1 = (%hash1, %hash2) ## or else ... @hash1{keys %hash2} = values %hash2; ## or with references ... $hash_ref1 = { %$hash_ref1, %$hash_ref2 }; </pre> <h2>Overview</h2> <ul> <li><strong>Context:</strong> Perl 5.x</li> <li><strong>Problem:</strong> The user wishes to merge two hashes<sup>1</sup> into a single variable </li> </ul> <h2>Solution</h2> <ul> <li>use the syntax above for simple variables</li> <li>use Hash::Merge for complex nested variables</li> </ul> <h2>Pitfalls</h2> <ul> <li>What do to when both hashes contain one or more duplicate keys <ul> <li>Should a key-value pair with an empty value ever overwrite a key-value pair with a non-empty value?</li> <li>What constitutes an empty vs non-empty value in the first place? (eg. <code>undef</code>, empty string, <code>false</code>, falsy ...)</li> <li>(Note: the original question rules out this scenario, but it is an important one to consider)</li> </ul></li> </ul> <h2>See also</h2> <ul> <li><a href="http://www.perlmonks.org/?node_id=524456" rel="noreferrer">PM post on merging hashes</a></li> <li><a href="http://www.perlmonks.org/?node_id=157715" rel="noreferrer">PM Categorical Q&A hash union</a></li> <li><a href="http://pleac.sourceforge.net/pleac_perl/hashes.html" rel="noreferrer">Perl Cookbook 5.10. Merging Hashes</a></li> <li>websearch://perlfaq "merge two hashes"</li> <li>websearch://perl merge hash</li> <li><a href="https://metacpan.org/pod/Hash::Merge" rel="noreferrer">https://metacpan.org/pod/Hash::Merge</a></li> </ul> <hr> <h2>Footnotes</h2> <p><sup>1</sup> * (aka <a href="https://stackoverflow.com/questions/tagged/associative-array">associative-array</a>, aka <a href="https://stackoverflow.com/questions/tagged/dictionary">dictionary</a>)</p>

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