R: expand and fill data frame by date in series

Question

I have the raw data frame:

igroup=c(\"A\", \"B\", \"C\")
demo_df=data.frame(date=c(\"2018-11-28\", \"2018-12-17\", \"2019-01-23\"), group)

Raw

Answer 1

First, make sure date is stored as a date object:

demo_df$date <- as.Date(demo_df$date, format = "%Y-%m-%d")

Then using tidyverse, we first complete the sequence, then fill the group down:

library(tidyverse)

demo_df %>% complete(date = seq.Date(min(date), max(date), by = "day")) %>% 
 fill(igroup)