How about this: > df1=data.frame(v1=c(1,1,2,3,2,4,1)) > df1$v2 <- ave(df1$v1,df1$v1,FUN=length) > df1 v1 v2 1 1 3 2 1 3 3 2 2 4 3 1 5 2 2 6 4 1 7 1 3
On Thu, Oct 16, 2008 at 1:27 PM, Lijiang Guo <[EMAIL PROTECTED]> wrote: > Dear R-helpers, > > I have a data frame with 3 variables, each record is a unique combination of > the three variables. I would like to count the number of unique values of v3 > in each v1, and save it as a new variable v4 in the same data frame. > e.g. > df1 > [v1] [v2] [v3] > [1,] "a" "C" "1" > [2,] "b" "C" "2" > [3,] "c" "B" "3" > [4,] "a" "B" "3" > [5,] "b" "A" "2" > [6,] "c" "A" "1" > > In this case, the 4th column would become (2, 1, 2, 2, 1, 2). > > Could someone tell me how to do this? > > regards, > Lijiang > > > -- > > [[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. > -- HUANG Ronggui, Wincent Tel: (00852) 3442 3832 Ph.D. Candidate, CityU of HK Master of sociology, Fudan University, China Bachelor of Social Work, Fudan University, China Personal homepage: http://ronggui.huang.googlepages.com/ ______________________________________________ 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.
