title: I want to add a copy of the first column as a new column at the end of the array, can someone explain the difference in dimentions of the error?
body: <pre><code>b = np.concatenate((a, a[:,0]), axis=1)
  </code></pre>
  <blockquote>
  <p>ValueError: all the input arrays must have same number of dimensions, but the array at index 0 has 2 dimension(s) and the array at index 1 has 1 dimension(s)</p>
  </blockquote>