title: Is arr.__len__() the preferred way to get the length of an array in Python?
body: <p>In <a href="http://en.wikipedia.org/wiki/Python_%28programming_language%29" rel="noreferrer">Python</a>, is the following the only way to get the number of elements?</p>
  
  <pre><code>arr.__len__()
  </code></pre>
  
  <p>If so, why the strange syntax?</p>