title: Pandas - formatting time and removing trailing zeros
body: <p>I have a column <code>Time</code> which looks like this:</p>
  
  <p><code>[df]</code></p>
  
  <pre><code>Date              Time  
  0  2017-02-05  00:00:02.0000000  
  1  2017-02-05  00:00:04.0000000  
  </code></pre>
  
  <p>I wish to convert a date_time type.</p>
  
  <p>The trailing decimal is always <code>0</code> and thus, can be removed.</p>
  
  <p><code>df['Time'] = pd.to_datetime(df['Time'],format='%H:%M:%S')</code></p>
  
  <p>However, this returns:</p>
  
  <p><code>ValueError: unconverted data remains: .0000000</code></p>