Adding missing date values in a data frame with multiple observation periods

Question

Thanks in advance.

I am trying to add missing date values that were not included in a observation period for three different individuals.

My data look like t

Answer 1

Try this.. This will add missing Dates with proper IDs and remaining fields as 0

library(data.table)
library(plyr)
dtPostData = data.table(PostData)
minmaxTab = dtPostData[,list(minDate=min(Date),maxDate=max(Date)),by=IndID]

df = lapply(1:nrow(minmaxTab),function(x) {
  temp = seq(minmaxTab$minDate[x],minmaxTab$maxDate[x],by=24*60*60) 
  temp = temp[!(temp %in% dtPostData[IndID == minmaxTab$IndID[x],]$Date)]
  data.table(IndID = minmaxTab$IndID[x], Date = temp, Event = 0, Number = 0, Percent = 0)
})

df <- ldply(x, data.frame)
df

#Results
   IndID       Date Event Number Percent
1    P01 2011-03-05     0      0       0
2    P01 2011-03-06     0      0       0
3    P01 2011-03-07     0      0       0
4    P01 2011-03-08     0      0       0
5    P01 2011-03-09     0      0       0
6    P01 2011-03-10     0      0       0
7    P01 2011-03-12     0      0       0
8    P01 2011-03-16     0      0       0
9    P03 2011-07-10     0      0       0