Hi, Try: dat <- read.table(text="Person Time Change 2 0 3 2 10 5 2 15 7 3 0 4 3 5 2",sep="",header=TRUE) dat1 <- transform(dat,Count= ave(rep(1,nrow(dat)), Person, FUN=cumsum)) #or ##If it is ordered by Person dat2 <- transform(dat, Count= setNames(sequence(table(Person)),NULL)) #or dat3 <- transform(dat,Count= ave(seq_along(Person), Person, FUN=seq_along)) all.equal(dat1,dat2) #[1] TRUE all.equal(dat1,dat3) #[1] TRUE
A.K. I have a dataframe that looks like this: Person Time Change 2 0 3 2 10 5 2 15 7 3 0 4 3 5 2 I would like to add a column that counts each row for each person, like this: Person Time Change Count 2 0 3 1 2 10 5 2 2 15 7 3 3 0 4 1 3 5 2 2 Thanks in advance! ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
