title: "list indices must be integers, not tuple" but it worked before?
body: <p>I have a 2d list of the form:</p>
  
  <pre><code>d = [[0.87768026489137663, -0.42848220833223599],
  [0.87770426313019434, -0.428411425505765],
  [0.87796388044104012, -0.42873867479872063],
  [0.87801587662514491, -0.42860583582101786],
  [0.87794315468933382, -0.42847396647067809]]
  </code></pre>
  
  <p>I want to get a single column from it, I've done this before on a different program using d[:,0] or d[:,1] and it worked perfectly.  But now when I try that I get the error: list indices must be integers, not tuple.  I know this must be a really simple fix but I'm just not sure whats wrong.  I'm using python 3.4 if that matters.</p>