title: how can I get the position of the nonzero values in a numpy array?
body: <p>I'm using np.nonzero() and i dont understand the return</p>
  
  <p>I try</p>
  
  <pre><code>for groupPosition in np.nonzero(groupMatrix):
      print groupPosition
  </code></pre>
  
  <p>and return [0 0 1 2 3 3 3]</p>
  
  <pre><code>for groupPosition in zip(np.nonzero(groupMatrix)):
      print groupPosition
  </code></pre>
  
  <p>and return (array([0, 1, 0, 3, 0, 1, 3]),)</p>
  
  <p>groupMatrix:</p>
  
  <pre><code>[[ 1.  1.  0.  0.]
  [ 1.  0.  0.  0.]
  [ 0.  0.  0.  2.]
  [ 3.  3.  0.  2.]]
  </code></pre>
  
  <p>But don't return the position like a (0, 0)</p>