title: How to find a column in a ndarray
body: <p>Say i have a array</p>
  
  <pre><code>x = array([[ 0,  1,  2, 5],
          [ 3,  4,  5, 5],
          [ 6,  7,  8, 5],
          [ 9, 10, 11, 5]])
  </code></pre>
  
  <p>I need to find the position/index of <code>[3, 4, 5, 5]</code>. In this case, it should return <code>1</code>.</p>