title: php array_filter anonymous function passing $this
body: <p>if want to do this following:</p>
  
  <pre><code>    $filteredValues = array_filter($rawValues, function($rawValue) {
          return $this-&gt;validateValue($rawValue);
      });
  </code></pre>
  
  <p><code>validateValue</code> is a private method in the same class.</p>
  
  <p>How can i use $this context in array_filter in this way?</p>