title: Remove all elements from QVector which are smaller than 0
body: <p>I have a <code>QVector</code></p>
  
  <pre><code> QVector(48, 64,  31, -2, 14, 5, 7, -3, -1, 13) 
  </code></pre>
  
  <p>I want to know how to use Qt mechanism to remove all the elements that are smaller than 0.<br><br>
  How do I do this in a simple way? <br>Thanks</p>