Dear R community; I'm kind of stuck with the following situation and would appreciate any hint. Let's assume I have the following data frame:
dat <- data.frame(ID = c(rep("01",18), rep("02",16)), USE = c(c("001","004", "005","007","001","004","005","007","012","001","004","005","007","001","004", "005","007","012"),c("004","005","007","013","001","004","005","007","001","004", "005","007","001","004","005","007")),ID2 = "") What I would like to achieve is to number all the "001" occurrences in USE for each ID individually and store them in ID2. In other words, something like this: ID USE ID2 1 01 001 1 2 01 004 3 01 005 4 01 007 5 01 001 2 6 01 004 7 01 005 8 01 007 9 01 012 10 01 001 3 11 01 004 12 01 005 13 01 007 14 01 001 4 15 01 004 16 01 005 17 01 007 18 01 012 19 02 004 20 02 005 21 02 007 22 02 013 23 02 001 1 24 02 004 25 02 005 26 02 007 27 02 001 2 28 02 004 29 02 005 30 02 007 31 02 001 3 32 02 004 33 02 005 34 02 007 Thanks again, Pedro [[alternative HTML version deleted]] ______________________________________________ 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.