title: Spread dataframe issue in Python pandas?
body: <p>I am trying to reformat / spread my dataframe from key, value columns to wide format:</p>
  <pre><code>test = pd.DataFrame({
  'id': [0,1,2,3,4,5,6,7],
  'a':['aa','bb', 'a', 'k', 'aa','bb', 'a', 'k'],
  'value': ['zzuz', 44, 'DE', 55, 'zdfdz', 454, 'SE', 155]})
  test.pivot(columns='a', values='value',index='id')
  </code></pre>
  <p>I want the outcome to be:</p>
  <pre><code>aa     bb  a  k
  zzuz   44  DE 55
  zdfdz  454 SE 155
  </code></pre>
  <p>I am trying to do this with .pivot without luck, please guide me what I am missing here?</p>
  <pre><code>test.pivot(columns='a', values='value')
  </code></pre>