You have *not* calculated row medians for all combinations of (is that what you meant?) 3 columns of your data frame. ?combn with column indexing can help you do that. If that is not what you meant, then ??
Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Thu, Apr 16, 2020 at 7:32 AM aiguo li via R-help <r-help@r-project.org> wrote: > > Hi all, > I need to calculate a row median for every three columns of a dataframe. I > made it work using the following script, but not happy with the script. Is > there a simpler way for doing this? > df = data.frame("a"=c(2,3,4), > "b"=c(3,5,1),"c"=c(1,3,6),"d"=c(7,2,1),"e"=c(2,5,3),"f"=c(4,5,1))tmed <- > function(dt) {x = apply(dt,1,median); return(x)}n =seq(1, ncol(df),3)w=0;for > (i in n) { m=i+2; dt = df[,i:m]; y=tmed(dt); w = cbind(w,y)}t.med <- > w[,2:3] > Thanks, > Anna > > > [[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. ______________________________________________ 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.