title: How to get values from a timestamp indexed dataframe
body: <p>I'm constructing a <code>DataFrame</code> like so:</p>
  
  <pre><code>dates = [datetime.datetime.today() + datetime.timedelta(days=x) for x in range(0, 2)]
  d = DataFrame([[1,2],[3,4]], index = dates, columns = ['a', 'b'])
  </code></pre>
  
  <p>I want to get a value like so:</p>
  
  <pre><code>d[d.index[0]]['a']
  </code></pre>
  
  <p>But I get the following error:</p>
  
  <pre><code>KeyError: Timestamp('2018-04-26 16:08:16.120031')
  </code></pre>
  
  <p>How come?</p>