title: How to extract hours from a pandas.datetime?
body: <p>I´ve a pandas dataframe which I applied the pandas.to_datetime. Now I want to extract the hours/minutes/seconds from each timestamp. I used df.index.day to get the days, and now, I want to know if there are different hours in my index.
  For example, if I have two dates d1 = 2020-01-01 00:00:00 and d2 = 2020-01-02 00:00:00 I can't assume I should apply a smooth operator by hour because makes no sense. </p>
  
  <p>So what I want to know is: how do I know if a day has different hours/minutes or seconds?</p>
  
  <p>Thank you in advance</p>