In R, is there a way to generate a list of random numbers per row of a dataframe?

Question

I want to use monte-carlo simulation to investigate the properties of certain kinds of dice systems which involve rolling a set of dice, and then picking the highest, possibly after having dropped the n highest dice.

To this end I've created a dataframe:

test <- data.frame(
  dice_to_roll = sample.int(4, 100, TRUE),
  highest_n_to_drop = sample(seq(0, 2), 100, TRUE)
)

Then for each row, I want to 'roll' a number of dice equal to dice_to_roll, and store them so that I can take max() or use nth() to drop a certain number, or perform other manipulations.

I know that

mutate(roll = max(sample.int(6, dice_to_roll, TRUE)))

doesn't work - it generates a single vector of length dice_to_roll, rather than a list for each row.

Is there an obvious way to do this that I'm missing?

Answer 1

Just found an answer for myself. Use rowwise:

    test <- test %>%
  rowwise() %>%
  mutate(
    results = max(sample.int(10, dice_to_roll, TRUE)))