Hi Anh, I know that it is not so elegant, but may work.
x<-runif(10) y<-runif(10)*2 z<-runif(10)*3 df<-data.frame(cbind(x,y,z)) df df$f<-NULL for (i in 1:nrow(df)) { df[i,"f"]<-max(c(df[i,"x"],df[i,"y"],df[i,"z"])) } Of course, others that know better apply family will solve if with a line :-) There are some functions for rowSums, rowMeans (see the help). Kind regards, miltinho On 6/24/08, Anh Tran <[EMAIL PROTECTED]> wrote: > > Hi, > Here's the data we have: > > > rs[1:5,] > probe_id f1 f2 f3 f4 M A f > 1 A_68_P20002076 2 58 0 0 1.51778114 6.344453 59 > 2 A_68_P20002775 22 8 15 0 0.43419304 5.488819 59 > 3 A_68_P20005791 43 3 0 0 0.05698666 9.830594 59 > 4 A_68_P20005805 11 34 0 0 1.71076835 6.624038 59 > 5 A_68_P20006729 16 44 0 0 0.85498261 6.044229 59 > > I want rs$f be the max of f1, f2, f3, f4 like a function in excel (=max(f1, > f2, f3, f4)). > > How should we do it in R? I'm not familiar with programing with list. So > please be patient > Thanks > -- > Regards, > Anh Tran > > [[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.