How to add only missing Dates in Dataframe

Question

I have below mentioned data frame:

Date        Val1     Val2
2018-04-01  125      0.05
2018-04-03  458      2.99
2018-04-05  354      1.25

Answer 1

You could use padr. padr is made for filling in missing date values. First you add the missing dates based on the interval, and if you do not want NA's you fill them with a value (or function of most occuring value)

edit: added end_val to include the run until sys.Date()

library(padr)
# Specify end_val to go all the way to sys.Date and add 1 to include sys.Date
padded_df <- pad(df, interval = "day", end_val = Sys.Date()+1)
padded_df <- fill_by_value(padded_df, value = 0)
padded_df

        Date Val1 Val2
1 2018-04-01  125 0.05
2 2018-04-02    0 0.00
3 2018-04-03  458 2.99
4 2018-04-04    0 0.00
5 2018-04-05  354 1.25
.....

31 2018-05-01    0    0
32 2018-05-02    0    0
33 2018-05-03    0    0
34 2018-05-04    0    0
35 2018-05-05    0    0
36 2018-05-06    0    0