My apologize, it has been solved. Just include w inside of select, such as: select = c(w, x, y)
On Fri, Oct 28, 2016 at 12:06 PM, lily li <chocol...@gmail.com> wrote: > Hi R users, > > I have the dataframe as below: > > w=c(5,6,7,8) > x=c(1,2,3,4) > y=c(1,2,3) > length(y)=4 > z=data.frame(w,x,y) > > z$mean1 <- rowMeans(subset(z, select = c(x, y)), na.rm = T) > z$mean2 <- rowMeans(subset(z, select = c(x, y)), na.rm=F) > > w x y mean1 mean2 > 1 5 1 1 1 1 > 2 6 2 2 2 2 > 3 7 3 3 3 3 > 4 8 4 NA 4 NA > > How to calculate mean value for the three columns, while default removing > NAs. > For example, for the fourth row, the mean value should be (8+4)/2 = 6 > > Thanks for your help. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.