This has nothing to do with order(). The following also reproduces the behavior:
> test <- data.frame(x=letters[1:5],y = 1:5) > test[1:5,]$z <- 11:15 Warning message: In `[<-.data.frame`(`*tmp*`, 1:5, , value = list(x = 1:5, y = 1:5, : provided 3 variables to replace 2 variables > test x y 1 a 1 2 b 2 3 c 3 4 d 4 5 e 5 > test$z <- 11:15 > test x y z 1 a 1 11 2 b 2 12 3 c 3 13 4 d 4 14 5 e 5 15 I don't know what's going on here, but it appears that it has something to do (again!) with the $ convenience syntax, which is best avoided, it seems. Instead of the rather convoluted syntax of the first statement, note that > test <- data.frame(x=letters[1:5],y = 1:5) > test[1:5,"z"] <- 11:15 > test x y z 1 a 1 11 2 b 2 12 3 c 3 13 4 d 4 14 5 e 5 15 ... works fine. Have you read "An Intro to R" where indexing is discussed? If not, why not? If so, please follow it. It will help you avoid such difficulties. -- Bert On Fri, Jul 27, 2012 at 1:22 PM, cowboy <dge...@gmail.com> wrote: > hi all, > I want to get a cumsum according to the order of some variable. > However, it doesnt' work. > For example, > ********************** > test<-data.frame(cbind(x=c(3,5,2,6,7),y=c(8,1,4,9,0))) > test[order(test$x),]$sumy<-cumsum(test[order(test$x),]$y) > ********************** > R complians Warning message: > In `[<-.data.frame`(`*tmp*`, order(test$x), , value = list(x = c(2, : > provided 3 variables to replace 2 variables. > > while the following > *********************** > test$sumy<-cumsum(test[order(test$x),]$y) > ****************** > gives > x y sumy > 1 3 8 4 > 2 5 1 12 > 3 2 4 13 > 4 6 9 22 > 5 7 0 22 > > should it gives > > x y sumy > 1 3 8 12 > 2 5 1 13 > 3 2 4 4 > 4 6 9 22 > 5 7 0 22 > > What am I missing here? > thanks, > Guang > > ______________________________________________ > 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. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ 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.
