title: Pandas -selecting data from last minute of hour for 24hr data
body: <p>Pandas beginner here.</p>
  
  <p>I have a 24 hour time series in minutes, with a cumulative value in column A:</p>
  
  <pre><code>Time                Energy
  11-01-2017 10:14    19.14634168
  11-01-2017 10:15    19.14702618
  11-01-2017 10:16    19.14719065
  11-01-2017 10:17    19.14719065
  …   
  11-01-2017 23:56    19.47694149
  11-01-2017 23:57    19.4771605
  11-01-2017 23:58    19.47753776
  11-01-2017 23:59    19.47801377
  </code></pre>
  
  <p>I would like to know what the value of column A is at the end of every hour (dd-mm-yyy hh:<strong>59</strong>), and save this data in a csv file, with an extra colum added to show the hour. The result would look like this:</p>
  
  <pre><code>   Time             Hour  Energy
     11-01-2017 00:59    1     02.0000000
     11-01-2017 01:59    2     04.1234554
     11-01-2017 02:59    3     06.1234554
     ...
     11-01-2017 23:59    24    19.4780137
  </code></pre>
  
  <p>Should I iterate the timeseries based on the seconds value of 59, or is it easier to just pluck the value in Column A every 60 rows, given there will always be 1440 rows (1440 minutes)?</p>