Dear all,

I'm writing you because I am stuck on this point.

I have a dataframe like this:

Rif year Var1 Var2

Name1 2015 11 15

Name1 2016 15 17

Name1 2017 10 12

Name1 2018 20 5

Name2 2015 26 10

Name2 2016 13 20

Name2 2017 5 7

Name3 2015 16 8

Name4 2015 19 11

Name4 2017 15 17

Name5 2017 21 9

Name5 2018 30 25

So, I am studying a period from 2015 to 2018, but there are missing values on some couples (Rif_year).

I would like to calcute the weighted mean for Var1 and Var2 with the following weights:

2018 = 0.5 -- 2017 = 0.3 -- 2016 = 0.15 -- 2015 = 0.05

For some Rif (Name2, Name3, Name4, Name5), Var1 e Var2 are missing on some years.

I would like to get all years for each Rif. Where I have the missing value, I would like to have row/rows containing Rif, the missing year/years, mode of Var1 and mode of Var2, where modes are computed on that specific Rif.

Hope to have been clear enough.

Thank you for your support!