number_of_files.R

#' Quickly count the number of files in a directory


number_of_files <- function(dir, filetype = "*.*") {
  if (.Platform$OS.type == "windows" &&
      nzchar(Sys.which("powershell"))) {
    current_wd <- getwd()
    on.exit(setwd(current_wd))
    setwd(dir)
    result <- system2("powershell",
                      args = c("-command", "Write-Host (dir . | measure).Count;"),
                      stdout = TRUE, 
                      stderr = "")
    # The following is faster via powershell but I can't invoke it
    # result <- system2("powershell", 
    #                   args = c("-command", '[System.IO.Directory]::GetFiles(".", "*.*").Count'))
    setwd(current_wd)
  } else {
    current_wd <- getwd()
    on.exit(setwd(current_wd))
    setwd(dir)
    result <- system("ls | wc -l", intern = TRUE)
    setwd(current_wd)
    
  }
  result
}