title: Append a 1d array to a 2d array in Numpy Python
body: <p>I have a numpy 2D array <code>[[1,2,3]]</code>.
  I need to append a numpy 1D array,( say <code>[4,5,6]</code>) to it, so that it becomes <code>[[1,2,3], [4,5,6]]</code></p>
  
  <p>This is easily possible using lists, where you just call <em>append</em> on the 2D list.</p>
  
  <p>But how do you do it in Numpy arrays?</p>
  
  <p><code>np.concatenate</code> and <code>np.append</code> dont work. they convert the array to 1D for some reason.</p>
  
  <p>Thanks!</p>