title: Accept String Parameter in Yii2 Action
body: <p>In my config file I've set the url rule like this :</p>
  
  <pre><code>&lt;controller:\w+&gt;/&lt;action:\w+&gt;/&lt;id:\d+&gt;' =&gt; '&lt;controller&gt;/&lt;action&gt;
  </code></pre>
  
  <p>And what happens is:-</p>
  
  <pre><code>controller/action/123 (work)
  controller/action/hello (not work)
  </code></pre>
  
  <p>But it accepts only digit as the parameter.<br>
  What I want is that both digit and string should be accepted.</p>
  
  <p>Please help!!!!</p>