Aggregate with numerous factors
Peter Dalgaard wrote:
Alternatively, rewrite aggregate() and send us a patch ;-) It is not necessarily all that hard. Here's a rough idea IX <- as.data.frame(by) OO <- do.call(order,IX) Y <- x[OO,] g <- cumsum(!duplicated(IX)) FF <- unique(IX) cbind(FF, sapply(split(x,g),FUN)) (completely untested, of course, and if it works, it works only for a single-column x; otherwise, you need a loop over the columns somehow.
I see two glaring blunders already... You need IX[OO,] in two places, and split(Y, g) not x
O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907