title: Delete certain rows in pandas dataframe with specific datetime value
body: <p>I have a dataframe where I am just interested in the values which occur for the full hour. That is how my data looks like:</p>
  
  <pre><code>0     2016-01-01 00:00:00  11.263
  1     2016-01-01 00:15:00  11.244
  2     2016-01-01 00:30:00  11.109
  3     2016-01-01 00:45:00  10.975
  4     2016-01-01 01:00:00  10.849
  </code></pre>
  
  <p>The dataframe has about 50 000 rows. What I want it to look like:</p>
  
  <pre><code>0     2016-01-01 00:00:00  11.263
  4     2016-01-01 01:00:00  10.849
  </code></pre>
  
  <p>I just want to see the values at full hours (1 am 2 am). Is there any possibility to do that? I have been trying out some stuff but it was not really working out. I have to admit that I am quite new to python. </p>
  
  <p>Thanks for any help! :) </p>