title: Most efficient way to sum a list in Python
body: <p>Among the ways to obtain the sum of a list <code>A</code> of ints in Python are the following two:</p>
  
  <ol>
  <li><p>Built-in <code>sum</code> function: <code>sum(A)</code></p></li>
  <li><p>Reduce function with adder lambda: <code>reduce(lambda x, y: x + y, A)</code></p></li>
  </ol>
  
  <p>Is there any speed advantage to using either of these, or are their performances roughly the same?</p>