title: Stacking arrays in numpy using vstack
body: <p><code>array1.shape</code> gives (180, )
  <code>array2.shape</code> gives (180, 1)</p>
  
  <p>What's the difference between these two?
  And because of this difference I'm unable to stack them using</p>
  
  <pre><code>np.vstack((array2, array1))
  </code></pre>
  
  <p>What changes should I make to array1 shape so that I can stack them up?</p>