title: Take first dimension in ndarray python
body: <p>Let's say I have a ndarray like this:</p>
  
  <pre><code>    a = [[20 43 61 41][92 23 43 33]]
  </code></pre>
  
  <p>I want take the first dimension of this ndarray. so I try something like this:</p>
  
  <pre><code>    a[0,:]
  </code></pre>
  
  <p>I hope it will return something like this:</p>
  
  <pre><code>    [[20 43 61 41]]
  </code></pre>
  
  <p>but i got this error:</p>
  
  <pre><code>   TypeError: 'numpy.int32' object is not iterable
  </code></pre>
  
  <p>Anyone can help me to solve this problem?</p>