title: date and hours from datetime [python]
body: <p>I have <code>datetime</code> parameter in pandas dataframe, with time that include minutes and seconds .</p>
  <pre><code> index                 date
  0         2021-03-01 07:55:00
  1         2021-03-01 07:56:13
  2         2021-03-01 07:56:43
  3         2021-03-01 07:57:19
  4         2021-03-01 07:57:57
         
  5         2021-03-01 11:39:25
  6         2021-03-01 11:39:59
  7         2021-03-01 11:40:53
  8         2021-03-01 11:41:44
  9         2021-03-01 11:43:31
  </code></pre>
  <p>how can I create parameter like this  (date and hour)</p>
  <pre><code>    index                   date
      0         2021-03-01 07:00:00
      1         2021-03-01 07:00:00
      2         2021-03-01 07:00:00
      3         2021-03-01 07:00:00 
      4         2021-03-01 07:00:00
             
      5         2021-03-01 11:00:00
      6         2021-03-01 11:00:00
      7         2021-03-01 11:00:00
      8         2021-03-01 11:00:00
      9         2021-03-01 11:00:00
  </code></pre>