Pandas: Backfilling Missig Data And Keeping The Index

I have a dataset with many missing value the time interval is 5min, however, there are many missing timestamp as well. Dataframe look like this: Time A 2000-01-01

Solution 1:

I found a solution that works:

df_filled=df.groupby(pd.Grouper(freq='10D')).fillna(method='bfill')