title: Concatenate 1D array to a 3D array
body: <p>I have a three dimensional array <code>A</code>, with shape <code>(5774,15,100)</code> and another 1 D array <code>B</code> with shape <code>(5774,)</code>. I want to add these in order to get the another matrix <code>C</code> with shape <code>(5774,15,101)</code>.</p>
  
  <p>I am using <code>hstack</code> as</p>
  
  <pre><code>C = hstack((A ,np.array(B)[:,None]))
  </code></pre>
  
  <p>I am getting the below error, any suggesstions.</p>
  
  <pre><code>ValueError: could not broadcast input array from shape (5774,15,100) into shape (5774)
  </code></pre>