title: how to convert a Series of arrays into a single matrix in pandas/numpy?
body: <p>I somehow got a <code>pandas.Series</code> which contains a bunch of arrays in it, as the <code>s</code> in the code below.</p>
  
  <pre><code>data = [[1,2,3],[2,3,4],[3,4,5],[2,3,4],[3,4,5],[2,3,4],
          [3,4,5],[2,3,4],[3,4,5],[2,3,4],[3,4,5]]
  s = pd.Series(data = data)
  s.shape # output ---&gt; (11L,)
  # try to convert s to matrix
  sm = s.as_matrix()
  # but...
  sm.shape # output ---&gt; (11L,)
  </code></pre>
  
  <p>How can I convert the <code>s</code> into a matrix with shape (11,3)? Thanks!</p>