On 04-11-2012, at 15:40, Bert Gunter wrote: > But ... > > On Sun, Nov 4, 2012 at 4:24 AM, Berend Hasselman <b...@xs4all.nl> wrote: >> >> On 04-11-2012, at 13:07, SHAILLY MEHROTRA wrote: >> >>> Dear R-users, >>> >>> I have dataset with column A and B with1000 values, >>> >>> For each of column C value (C = seq(1,1000,1), I want to repeat A and B >>> values and calculate R = A+B*C for each row. >>> >>> I want to get output as >>> >>> A B C R >>> 1 10 1 11 >>> 2 30 1 32 >>> 3 50 1 53 >>> 1000 1000 1 2000 >>> 1 10 2 21 >>> 2 30 2 62 >>> 3 50 2 103 >>> 1000 1000 2 3000 >>> >>> How can I do it using for loop? >>> >> >> You don't do that with a for loop. >> You can do it like this, assuming your dataset is a data.frame and is named >> "dat" >> >> >> dat["R"] <- dat["A"] + dat["B"]*dat["C"] > > dat[["R"]] <- dat[["A"]] + dat[["B"]]*dat[["C"]] > > would be better, I believe. >
Right. I insert the reply which was sent to me and not to the R-help list: > > I think you misunderstood my question. > > In my dataset, I have only two columns.( A and B with 1000 values each). > I generated a variable C using seq(1,4200,20). > Now for each value of C, I want to calculate 1000 R values (using 1000 - A > and 1000 - B values) > Finally, I want to have a dataset in which for each C value , I have 1000 R > values. > > So the final dataset should have 210*1000 rows. > > Hope it is clear now. > Well try this then: dat <- read.table(text=" A B 1 10 2 30 3 50 1000 1000 1 10 2 30 3 50 1000 1000", header=TRUE) dat[,"C"] <- rep(1:2,each=nrow(dat)/2,length.out=nrow(dat)) dat[,"R"] <- unlist(lapply(split(dat,dat$C), FUN=function(x) x$A+x$B*x$C)) dat Berend > And the OP would be well-advised to read the Intro to R tutorial > before posting further on this list. > > To quote Rolf Turner on this list: > > " Learn something about R; don't just hammer and hope. Read the > introductory manuals and scan the FAQ.." > > -- Bert > >> >> dat[,"R"] <- dat[,"A"] + dat[,"B"]*dat[,"C"] >> >> Read the R intro manual. >> >> Berend ______________________________________________ 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.
