title: How to test if a value exist in a hash?
body: <p>Let's say I have this</p>
  
  <pre><code>#!/usr/bin/perl
  
  %x = ('a' =&gt; 1, 'b' =&gt; 2, 'c' =&gt; 3);
  </code></pre>
  
  <p>and I would like to know if the value 2 is a hash value in <code>%x</code>.</p>
  
  <p>How is that done?</p>