Monty Hall Problem

monty_hall.R

reveal_door <- function(doors) {

  if ("car" %in% names(doors)) {
    return(doors[names(doors) != "car"])
  }

  sample(doors, size = 1)
}

play_monty_hall <- function(switch_doors = FALSE) {

  # setup the doors 1 to 3 randomly
  door_names <- sample(c("goat", "goat", "car"), size = 3, replace = FALSE)
  three_doors <- setNames(1:3, nm = door_names)

  # player chooses door
  chosen_door <- sample(three_doors, size = 1)

  # in case player uses "switching strategy"
  if (switch_doors) {
    remaining_doors <- three_doors[-chosen_door]
    revealed_door <- reveal_door(remaining_doors)
    finally_remaining_door <- remaining_doors[remaining_doors != revealed_door]
    chosen_door <- finally_remaining_door
  }

  # check if player gets car
  names(chosen_door) == "car"

}

sum(replicate(10000, play_monty_hall(switch_doors = FALSE)))
sum(replicate(10000, play_monty_hall(switch_doors = TRUE)))