title: python list comprehension: gathering duplicate columns
body: <p>I have a sorted list of lists that contain duplicate first elements.
  Currently I'm iterating over it to get the solution.</p>
  
  <pre><code>[['5th ave', 111, -30.00, 38.00],
  ['5th ave', 222, -30.00, 33.00],
  ['6th ave', 2224, -32.00, 34.90]]
  </code></pre>
  
  <p>I'd like an elegant list comprehension to convert this to a list of lists based on the first element:</p>
  
  <p><code>['5th ave',  [[111, -30.00, 38.00] , [222, -30.00, 33.00]]</code></p>
  
  <p>Thanks</p>