title: numpy array TypeError: only integer scalar arrays can be converted to a scalar index
body: <pre><code>i=np.arange(1,4,dtype=np.int)
  a=np.arange(9).reshape(3,3)
  </code></pre>
  
  <p>and</p>
  
  <pre><code>a
  &gt;&gt;&gt;array([[0, 1, 2],
            [3, 4, 5],
            [6, 7, 8]])
  a[:,0:1]
  &gt;&gt;&gt;array([[0],
            [3],
            [6]])
  a[:,0:2]
  &gt;&gt;&gt;array([[0, 1],
            [3, 4],
            [6, 7]])
  a[:,0:3]
  &gt;&gt;&gt;array([[0, 1, 2],
            [3, 4, 5],
            [6, 7, 8]])
  </code></pre>
  
  <p>Now I want to vectorize the array to print them all together. I try</p>
  
  <pre><code>a[:,0:i]
  </code></pre>
  
  <p>or</p>
  
  <pre><code>a[:,0:i[:,None]]
  </code></pre>
  
  <p>It gives TypeError: only integer scalar arrays can be converted to a scalar index</p>