That works if I want a count of each group but I needed a count of the number of groups. Michael answered that question with length(unique(ID)) However, this doesn't supply a title, it is just a number. I need it to still have the identifier 'ID'.
Regards, Charles On Fri, May 25, 2012 at 11:50 AM, Steve Friedman <skfgla...@gmail.com>wrote: > ?table > On May 25, 2012 11:46 AM, "Charles Determan Jr" <deter...@umn.edu> wrote: > >> Hello, >> >> Simple question that I am stuck on and can't seem to find an answer in the >> help files currently. I have a list which contains repeated ID's. I >> would >> like to have R count the number of ID's. For example: >> >> ID=c(1,1,1,1,2,2,2,2,3,3,3,3) >> as.data.frame(ID) >> >> Clearly, there are 3 groups. How would I have R give me the summary: >> >> ID >> 3 >> >> Many thanks, >> Charles >> >> [[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. >> > [[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.
