title: Extract first item of each sublist
body: <p>I am wondering what is the best way to extract the first item of each sublist in a list of lists and append it to a new list. So if I have:</p>
  
  <pre><code>lst = [[a,b,c], [1,2,3], [x,y,z]]
  </code></pre>
  
  <p>and I want to pull out <code>a</code>, <code>1</code> and <code>x</code> and create a separate list from those.</p>
  
  <p>I tried:</p>
  
  <pre><code>lst2.append(x[0] for x in lst)
  </code></pre>