title: Python 2.7 current row index on 2d array iteration
body: <p>When iterating on a 2d array, how can I get the current row index? For example:</p>
  
  <pre><code>x = [[ 1.  2.  3.  4.]
       [ 5.  6.  7.  8.]
       [ 9.  0.  3.  6.]]
  </code></pre>
  
  <p>Something like:</p>
  
  <pre><code>for rows in x:
     print x current index (for example, when iterating on [ 5.  6.  7.  8.], return 1)
  </code></pre>