You can try this:
data <- cbind("a"=sample(1:10), "b"=sample(1:10))
fact <- sample(rep(1:1, each=10))
system.time(std <- by(data, fact, colSums))
by.matrix <- function (data, INDICES, FUN, ...) {
if (!is.list(INDICES)) {
IND <- vector("list", 1)
IND[[1]] <- INDIC
Full_Name: Simon de Bernard
Version: 2.7.0 (44733)
OS: MacOS
Submission from: (NULL) (140.77.34.213)
"by" usually takes forever even on a "not so large" data structure.
If one can do with a matrix instead of a data.frame, defining by.matrix as
by.data.frame modified to convert data back to a dat
Full_Name: Simon de Bernard
Version:
OS:
Submission from: (NULL) (140.77.34.213)
In src/main/dotcode.c, function RObjToCPtr, test for naok should be transferred
outside of the loops...
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