title: Concatenate a NumPy array to another NumPy array
body: <p>I have a numpy_array. Something like <code>[ a b c ]</code>.</p>
  <p>And then I want to concatenate it with another NumPy array (just like we create a list of lists). How do we create a NumPy array containing NumPy arrays?</p>
  <p>I tried to do the following without any luck</p>
  <pre><code>&gt;&gt;&gt; M = np.array([])
  &gt;&gt;&gt; M
  array([], dtype=float64)
  &gt;&gt;&gt; M.append(a,axis=0)
  Traceback (most recent call last):
   File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
  AttributeError: 'numpy.ndarray' object has no attribute 'append'
  &gt;&gt;&gt; a
  array([1, 2, 3])
  </code></pre>