EVOLUTION-MANAGER

Edit File: isplit.R

# iterator for splitting data using a factor library(foreach) # let's use isplit on a data frame a <- foreach(i=isplit(airquality, airquality$Month), .combine=rbind) %do% quantile(i$value, na.rm=TRUE) # make it pretty and print it rownames(a) <- levels(as.factor(airquality$Month)) print(a) # use a list of factors to do an aggregated operation it <- isplit(as.data.frame(state.x77), list(Region=state.region, Cold=state.x77[,'Frost'] > 130), drop=TRUE) a <- foreach(i=it, .combine=rbind) %do% { x <- mean(i$value) dim(x) <- c(1, length(x)) colnames(x) <- names(i$value) cbind(i$key, as.data.frame(x)) } print(a) # compare with the standard aggregate function b <- aggregate(state.x77, list(Region=state.region, Cold=state.x77[,'Frost'] > 130), mean) print(b) cat('results identical:\n') print(identical(a, b))