sorry, i forgot list(): t(as.matrix(aggregate(t(as.matrix(DF)), list(rep(1:12,each=3)), mean)[,-1]))
michael watson (IAH-C) a écrit : >Hi > >I've been reading the help for by and aggregate but can't get my head >round how to do this. > >I have a data frame - the first three columns are replicate >measurements, then the next 3 are replicates etc up to 36 (so 12 >variables with 3 replicate measurements each). I want to compute the >mean for each of the 12 variables, so that, for each row, I have 12 >means. > >A grouping variable across columns can easily be created by >rep(1:12,each=3), but I can't figure out which function to use to get R >to calculate the means I want. > >Thanks in advance >Mick > >______________________________________________ >R-help@stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html