title: Time series in panda
body: <p>How do I convert  a <code>date index</code> into <em>Time-based indexin</em>g?
  so that i can later generate a month, weekday and a year</p>
  
  <p>I tried this code </p>
  
  <pre><code>df['TRANS_DATE'] = pd.to_datetime(df['TRANS_DATE'], format='%m/%d/%Y %H:%M:%S')
  </code></pre>
  
  <p>but after I change it to Index the date revert back to show as object</p>