R/report_p.R

In johnellis30/demopckg: Demo Tutorial

#' Report p-value
#'
#' Reports a p-value in APA style
#'
#' @param p The p-value
#' @param digits The number of digits to round to (default = 3)
#'
#' @return A string with the format "p = .040" or "p < .001"
#'
#' @examples
#'
#' report_p(0.02018) # returns "p = .020"
#' report_p(0.00028) # returns "p < .001"
#'
#' @export


report_p <- function(p, digits = 3) {

  # error checking
  if (p < 0) stop("p cannot be less than 0")
  if (p > 1) stop("p cannot be greater than 1")
  if (!(digits %in% 1:5)) {
    warning("digits should probably be an integer between 1 and 5")
    digits = 3
  }

  if (p < .001) return("p < .001")

  p_round <- round(p, digits) %>%
    as.character() %>%

    # omit leading zero for APA-style
    stringr::str_replace("0.", ".") %>%

    # pad right with zeros
    stringr::str_pad(digits + 1, "right", 0)


  p_string <- paste("p =", p_round)


  return(p_string)
}

report_p(.01034)