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PODoes Ruby have a way to return a reference, similar to PHP?
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  1. PODoes Ruby have a way to return a reference, similar to PHP?
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    copied!<p>In PHP I can use <code>&amp;</code> to assign the <code>reference</code> of a variable to another variable as seen in the first code snippet below.</p> <blockquote> <p>See PHP "Returning References" documentation for some more context... <a href="http://www.php.net/manual/en/language.references.return.php" rel="nofollow">http://www.php.net/manual/en/language.references.return.php</a></p> </blockquote> <p>PHP Code:</p> <pre><code>&lt;?php $tree = array(); $tree["branch"] = array(); $tree["branch"]["leaf"] = "green"; echo '$tree: '; var_dump($tree); $branch = &amp;$tree["branch"]; $branch = "total replacement!"; echo '$tree: '; var_dump($tree); ?&gt; </code></pre> <p>PHP's output:</p> <pre><code>$tree: array(1) { ["branch"]=&gt; array(1) { ["leaf"]=&gt; string(5) "green" } } $tree: array(1) { ["branch"]=&gt; &amp;string(18) "total replacement!" } </code></pre> <p>Trying to do this in Ruby I did:</p> <pre><code>tree = {} tree["branch"] = {} tree["branch"]["leaf"] = "green" puts "tree: #{tree.inspect}" branch = tree["branch"] branch = "total replacement!" puts "tree: #{tree.inspect}" </code></pre> <p>Which output:</p> <pre><code>tree: {"branch"=&gt;{"leaf"=&gt;"green"}} tree: {"branch"=&gt;{"leaf"=&gt;"green"}} </code></pre> <p>Now, while this straight assignment does not work in Ruby, modification of the object does:</p> <p>Ruby Code (Continued):</p> <pre><code>branch["lead"] = "red" puts "tree: #{tree.inspect}" </code></pre> <p>Ruby's Output:</p> <pre><code>tree: {"branch"=&gt;{"leaf"=&gt;"red"}} </code></pre> <p>So, I'm left wondering if there is a way to find the "parent" of an object so that I might modify it like I've done with <code>branch["leaf"]</code>.</p> <p><strong>Author Edit:</strong></p> <p>While one <strong>can't</strong> change a hash reference to any other variable through assignment (e.g., <code>x = y</code>), one <strong>can</strong> modify the existing object through its methods. Using this approach one can <em>pseudo-assign</em> a new <code>hash</code> to the <code>branch</code> variable using <code>.replace()</code> as seen below...</p> <p>Replacement Instead of Assignment:</p> <pre><code>tree = {} tree["branch"] = {} tree["branch"]["leaf"] = "green" puts "tree: #{tree.inspect}" branch = tree["branch"] branch.replace({"leaf" =&gt; "red", "twig" =&gt; "brown"}) puts "tree: #{tree.inspect}" </code></pre> <p>Output: </p> <pre><code>tree: {"branch"=&gt;{"leaf"=&gt;"green"}} tree: {"branch"=&gt;{"leaf"=&gt;"red", "twig"=&gt;"brown"}} </code></pre>
 

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