preallocate list in R

Question

It is inefficient in R to expand a data structure in a loop. How do I preallocate a list of a certain size? matrix makes this easy via the ncol and nrow arguments. How does one do this in lists? For example:

x <- list() for (i in 1:10) {     x[[i]] <- i } 

I presume this is inefficient. What is a better way to do this?

Answer 1

vector can create empty vector of the desired mode and length.

x <- vector(mode = "list", length = 10)