熊猫按比例向前填充

Question

I have a dataframe like this:

Month/Year  Value  
01/2018     100  
03/2018     200  
06/2018     800  

The values for 02/2018, 04/2018 and 05/2018 is missing because the value did not change in those months. I would like to have a dataframe which incudes the missing months and values are increased proportionally:

Month/Year  Value    
01/2018     100  
02/2018     150  
03/2018     200   
04/2018     400  
04/2018     600  
06/2018     800 

Thank you for help with the solution!

Answer 1

First convert column to DatetimeIndex , add missing datetimes by asfreq , interpolate and if necessary same format add strftime :

df['Month/Year'] = pd.to_datetime(df['Month/Year'], format='%m/%Y')
df = df.set_index('Month/Year').asfreq('MS').interpolate().reset_index()
df['Month/Year'] = df['Month/Year'].dt.strftime('%m/%Y')
print (df)
  Month/Year  Value
0    01/2018  100.0
1    02/2018  150.0
2    03/2018  200.0
3    04/2018  400.0
4    05/2018  600.0
5    06/2018  800.0