title: How to take same index element from a list with 2 lists
body: <p>Lets say I have the following list:</p>
  
  <pre><code>a = [[1,2,3],[4,5,6],[7,8,9]]
  </code></pre>
  
  <p>Is there a way to sum all the seconds elements <strong>without using loop</strong>? Such as:</p>
  
  <pre><code>the_sum = 0
  for num in a:
      the_sum += num[1]
  &gt;&gt;&gt; 15
  </code></pre>