Displaying 1 result from an estimated 1 matches for "splitwithnames".
2004 Apr 08
1
Why are Split and Tapply so slow with named vectors, why is a for loop faster than mapply
...<- split(actTime, chainId))
Timing stopped at: 83.22 0.12 84.49 NA NA
The same thing happens with using tapply with a named vector such as:
tapply(actTime, chainId, function(x) x)
Using the following function with a for loop accomplishes the job in a few
seconds for all 70,000+ records:
> splitWithNames <- function(dataVector, nameVector, factorVector){
+ dataList <- split(dataVector, factorVector)
+ nameList <- split(nameVector, factorVector)
+ listLength <- length(dataList)
+ namedDataList <- list(NULL)
+ for(i in 1:listLength){
+ x <- dataList[[i]]...