title: How to remove a certain time period from a dataframe with timestamp index?
body: <p>I have a DataFrame that is something like this:</p>
  
  <pre><code>Datetime             Open   Low/Open  Close/Open  Tar
  
  1998-01-30 15:30:00  68.02  0.997501    0.999706    0
  1998-01-30 15:45:00  67.91  0.998086    1.000736    0
  1998-01-30 16:00:00  67.96  0.998676    1.000589    0
  1998-01-30 16:15:00  67.96  1.000000    1.000000    0
  </code></pre>
  
  <p>the timestamp is 24 hours, however, I only want the data points that have index between 9:30:00 to 16:00:00. How do I remove all the data points outside of what I need?</p>