title: Numpy: proper way to arrange input and output vectors
body: <p>I am trying to create a numpy array with 2 columns and multiple rows. The first column is meant to represent input vector of size 3. The 2nd column is meant to represent output vector of size 2.</p>
  
  <pre><code>arr = np.array([
      [np.array([1,2,3]), np.array([1,0])]
      [np.array([4,5,6]), np.array([0,1])]
  ])
  </code></pre>
  
  <p>I was expecting: <code>arr[:, 0].shape</code>
  to return (2, 3), but it returns (2, )</p>
  
  <p>What is the proper way to arrange input and output vectors into a matrix using numpy?</p>