R/utils.R

In benjaminleroy/coin: R Coin Object Example

#' check if probability vector is as expected
#'
#' @param prob probability vector
#'
#' @return TRUE or errors
#' @export
check_prob <- function(prob) {
  assertthat::assert_that(is.numeric(prob),
                          msg = "'prob' must be a numeric vector")

  assertthat::assert_that(length(prob) == 2 & is.numeric(prob),
                          msg = "'prob' must be a numeric vector of length 2")

  assertthat::assert_that(all(prob >= 0) & all(any(prob <= 1)),
                          msg = "'prob' values must be between 0 and 1")

  assertthat::assert_that(sum(prob) == 1,
                         msg = "elements in 'prob' must add up to 1")
  TRUE
}

print.coin <- function(coin){
  cat(paste0("Coin: ", coin[1], "/", coin[2], "\n"))
  prob <- attr(coin, "prob")
  cat(paste0("  Prob: ", prob[1], "/", prob[2], "\n"))
}

print.rare_coin <- function(coin){
  cat(paste0("Rare coin: ", attr(coin, "name"),
             ", ", attr(coin, "year"), "\n"))
  print.coin(coin)
}