Comparing the size of expand.grid with a list of functions of the same size.

gistfile1.r

gsize <- function(n) {
  grid <- expand.grid(rep(list(1:10), n))
  object.size(grid) / 1024
}

fsize <- function(n) {
  f <- function(i) {force(i) ; function(j) { i + j}}
  flst <- lapply(1:(10^n), f)
  object.size(flst) / 1024
}

# a function to compare object sizes
comparison <- function(n) {
  fsize(n) - gsize(n)
}

# > sapply(1:5, comparison)
# [1]     3.796875    47.585938   486.140625  4841.140625 48043.718750