Script to read a directory of data similar to `read_dir` but using drake to remember what has already been read.

read_dir_with_drake.R

library("drake")

files = list.files("data", "*.csv", full.names = TRUE)

add2 = function(d) { # example function to apply to each individual data.frame
  d$x = d$x+2
  return(d)
}

plan = drake_plan(
  data  = target(
    read.csv(file_in(file)),
    transform = map(file = !!files)
  ),
  add2  = target(
    add2(data),
    transform = map(data)
  ),
  all = target(
    dplyr::bind_rows(add2),
    transform = combine(add2)
  ),
  out = saveRDS(all, file = file_out("all.RDS"))
)

plan
make(plan)