Monte Carlo simulation in R for Monty Hall problem not working?

Question

I'm writing a function in R to perform a Monte Carlo simulation for the Monty Hall problem. The function is working when the doors are not switched it switch == FALSE, but when I call mean(replicate(10000, monty_hall(switch = TRUE))), the expected answer is about 0.66 but I actually get around 0.25.

Here is the code to the function:

monty_hall = function(switch = logical()){

    doors <- c(1,2,3)

    names(doors) <- rep(c("goat", "car"), c(2,1))

    prize_door <- doors[3]

    guess <- sample(doors, 1)

    revealed_door <- sample(doors[!doors %in% c(guess, prize_door)],1)

    if(switch){

        switched_door <- sample(doors[!doors %in% c(guess, revealed_door)],1)

        prize_door == switched_door

    } else {

        prize_door == guess

        }

}

What changes should I make to get the correct output, which is around 0.66?

Answer 1

You just need to change doors vector to characters in order to get the correct output.

monty_hall = function(switch = logical()){

   doors <- c("1","2","3")

   names(doors) <- rep(c("goat", "car"), c(2,1))

   prize_door <- doors[3]

 

   guess <- sample(doors, 1)

   revealed_door <- sample(doors[!doors %in% c(guess, prize_door)],1)

   if(switch){

      switched_door <- sample(doors[!doors %in% c(guess, revealed_door)],1)

      prize_door == switched_door

   } else {

      prize_door == guess

   }

}

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