Fill missing combinations in a dataframe
Solution 1:
Using complete from tidyr:
library(tidyr)
as.data.frame(complete(df,REGION,CATEGORY,fill=list(VALUE1=0,VALUE2=0)))
Output:
REGION CATEGORY VALUE1 VALUE2
1 REGION A A 2 1
2 REGION A B 3 2
3 REGION B A 0 0
4 REGION B B 4 3
If there are many variables, you could also just do as.data.frame(complete(df,REGION,CATEGORY)) and replace the NA's afterwards.
Hope this helps!