R fill missing dates by category

问题

x<-data.frame(product=c(rep("A",3),rep("B",4)),
          xdate=as.Date(c("2020-01-01","2020-01-02","2020-01-04",'2020-01-02','2020-01-04','2020-01-07','2020-01-08')),
          number=sample(1:10,7))

In sample data I want to fill missing dates by category. In the sample data it means that for category A I want all missing dates between it's minimum date 2020-01-01 and maximum '2020-01-04 and the same logic for category B. I am aware of function complete but it seems like it's insufficient for what I am looking for. And the number variable should be filled with 0s

回答1:

We can use complete here as well :

library(dplyr)
library(tidyr)

x %>%
  group_by(product) %>%
  complete(xdate = seq(min(xdate), max(xdate), by = "1 day"), fill = list(number = 0))

来源：https://stackoverflow.com/questions/60724664/r-fill-missing-dates-by-category