title: PHP / bitwise operators left shift
body: <p>Can someone please explain to me why this equals <code>32</code>?</p>
  
  <pre><code>$a = 4 &lt;&lt; 2 + 1;
  echo $a;
  </code></pre>
  
  <p>Output:</p>
  
  <blockquote>
    <p>32</p>
  </blockquote>
  
  <p>I read the <a href="http://php.net/manual/en/language.operators.bitwise.php" rel="nofollow">manual</a> and found out that <code>&lt;&lt;</code> is a bit shift left, but still don't quite grasp the concept.</p>