title: Find index of longest sub-list in 2D list
body: <p>I originally had two arrays, one contained numbers, the other associated values:</p>
  
  <pre><code>scores =  [2,            4,     12 ... etc ]
  players = ["Peter", "Brian", "Meg" ... etc]
  top_score_index = scores.index(max(scores))
  top_player = players[top_score_index]
  </code></pre>
  
  <p>This already stinks, because the <code>scores.index(max(scores))</code> obviously iterates over that list twice (in the worst case scenario).</p>
  
  <p>Situation changed, the <code>scores</code> array now contains lists:</p>
  
  <pre><code>scores = [[something, something, something], [something, something]]
  </code></pre>
  
  <p>The score which I care about is however simply <code>len( scores[some_offset] )</code>, that is the length of nested list.</p>
  
  <p>How can I easily find the index of longest of those nested lists? Eg. for:</p>
  
  <pre><code>[[0,0,0],[0,0],[0,0,0,0,0,0]]
  </code></pre>
  
  <p>I would expect return value of <code>2</code>. Please that <strong>efficiency is a concern</strong> for me right now.</p>