R/pretty_round_p_value.R

In ezr: Easy Use of R via Shiny App for Basic Analyses of Experimental Data

#' Pretty round p-value
#'
#' @param p_value_vector one number or a numeric vector
#' @param include_p_equals if \code{TRUE}, output will be a string of
#' mathematical expression including "p", e.g., "p < .01"
#' @param round_digits_after_decimal
#' round to nth digit after decimal
#' @examples
#' pretty_round_p_value(p_value_vector = 0.049,
#' round_digits_after_decimal = 2, include_p_equals = FALSE)
#' pretty_round_p_value(c(0.0015, 0.0014), include_p_equals = TRUE)
#' @export
#' @importFrom stats model.frame pf
pretty_round_p_value <- function(
  p_value_vector = NULL,
  round_digits_after_decimal = 3,
  include_p_equals = FALSE) {
  if (is.numeric(p_value_vector)) {
    if (include_p_equals == TRUE) {
      output <- ifelse(
        p_value_vector < .001, "p < .001",
        paste0(
          "p = ", sub(
            "^(-?)0.", "\\1.",
            sprintf(
              paste0("%.", round_digits_after_decimal, "f"),
              p_value_vector))))
      return(output)
    }
    output <- ifelse(
      p_value_vector < .001, "< .001",
      sub("^(-?)0.", "\\1.",
          sprintf(
            paste0("%.", round_digits_after_decimal, "f"),
            p_value_vector)))
    return(output)
  } else if (is.character(p_value_vector)) {
    stop(paste0("The vector, p_value_vector, is a character",
                " vector, rather than a numeric vector"))
  } else {
    stop(paste0("The vector, p_value_vector, is neither",
                " a character vector nor a numeric vector"))
  }
}