title: Drop Python Pandas dataframe rows based on date in index
body: <p>I have a Python Dataframe that looks like this:</p>
  
  <pre><code>                        Facility   PUE   PUEraw   Servers
  2016-11-14 00:00:00     6.0        NaN   1.2      5.0 
  2016-11-14 00:30:00     6.0        NaN   1.2      5.0 
  2016-11-14 01:00:00     6.0        NaN   1.2      5.0 
  </code></pre>
  
  <p>etc.</p>
  
  <p>As you can see, the index is date/time. The dataframe is updated with a new value every half hour.</p>
  
  <p>I'm trying to write a script that removes all rows except those that correspond to TODAY's date, for which I am utilising date = dt.datetime.today(). However, I am struggling, partly perhaps because the index also contains the time.</p>
  
  <p>Does anyone have any suggestions? Alternatively, a script that removes all but the last 48 rows would also work for me (the last 48 x half hourly values = the latest day's data).</p>