How to append hour:min:sec to the DateTime in pandas Dataframe

Question

I have following dataframe, where date was set as the index col,

date	renormalized
2017-01-01	6
2017-01-08	5
2017-01-15	3
2017-01-22	3
2017-01-29	3

I want to append 00:00:00 to each of the datetime in the index column, make it like

date	renormalized
2017-01-01 00:00:00	6
2017-01-08 00:00:00	5
2017-01-15 00:00:00	3
2017-01-22 00:00:00	3
2017-01-29 00:00:00	3

It seems I got stuck for no solution to make it happen.... It will be great if anyone can help...

Thanks

AL

Answer 1

When your time is 0 for all instances, pandas doesn't show the time by default (although it's a Timestamp class, so it has the time.), Probably your data is already normalized. and you can perform delta time operations as usual.

You can see a target observation with df.index[0] for instance, or take a look at all the times with df.index.time .

Answer 2

You can use DatetimeIndex.strftime

df.index = pd.to_datetime(df.index).strftime('%Y-%m-%d %H:%M:%S')

print(df)

                     renormalized
date
2017-01-01 00:00:00             6
2017-01-08 00:00:00             5
2017-01-15 00:00:00             3
2017-01-22 00:00:00             3
2017-01-29 00:00:00             3

Or you can choose

df.index = df.index + ' 00:00:00'