title: Adding rows to an empty 2D NumPy array
body: <p>I want to start with an empty 2D  NumPy array, and then add some rows to it. However, so far I have only been able to do this with a 1D array. Here is what I have tried so far:</p>
  
  <pre><code>a = numpy.array([])
  a = numpy.append(a, [1, 2])
  a = numpy.append(a, [8, 8])
  print a
  </code></pre>
  
  <p>The output I get is:</p>
  
  <pre><code>[1, 2, 8, 8]
  </code></pre>
  
  <p>Whereas I want the output to be:</p>
  
  <pre><code>[[1, 2], [8, 8]]
  </code></pre>
  
  <p>How can I do this?</p>