title: Lexicographic sort float array python
body: <p>Okay, so, I have a 4x2 numpy ndarray, and I want to sort it lexicographically. That is, if I have the array</p>
  
  <pre><code>[[0,0],
  [1,1],
  [0,1],
  [1,0]]
  </code></pre>
  
  <p>I want it to become</p>
  
  <pre><code>[[0,0],
  [0,1],
  [1,0],
  [1,1]]
  </code></pre>
  
  <p>How do I do this?</p>