title: Convert string with hex ASCII codes to characters
body: <p>I have a string containing hex code values of ASCII characters, e.g. <code>"666f6f626172"</code>. I want to convert it to the corresponding string (<code>"foobar"</code>).</p>
  
  <p>This is working but ugly:</p>
  
  <pre><code>"666f6f626172".scan(/../).map(&amp;:hex).map(&amp;:chr).join # =&gt; "foobar"
  </code></pre>
  
  <p>Is there a better (more concise) way? Could <code>unpack</code> be helpful somehow?</p>