> > I'm no expeRt, but suppose that we change the setup slightly: > > xx <- x[sample(nrow(x)), ] > > Now what would you like > > aggregate(value ~ group + year, data=xx, FUN=function(z) z[1]) > > to return? > > Personally, I prefer to have R return the same thing regardless > of how the input dataframe is sorted,
Personally, I prefer to have R not to change my input as much as possible... but I totally agree with you that there are other instances where it's preferable that the output does not depend on the input. > i.e. the result should depend only on the formula. You just have to know that > the order is to have the first factor vary most rapidly, ... which I still find very confusing/unnatural, but okay. > then the next, etc. I think that's documented somewhere, but I don't know > where. it's also the default behavior of expand.grid() for example. Cheers, Marius > > > Peter Ehlers > ______________________________________________ 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.
