title: How can i convert string to int and then sort view by int value?
body: <p>I want sort view by a value that is string. but before that, i want convert string to int then sort by that.</p>
  <pre><code>main = models.Main.objects.all().order_by('fore_key__n')
  </code></pre>
  <p>In this code <code>fore_key__n</code> is string value like '20'</p>