style_percent.R

#' Style percentages
#'
#' @param x numeric vector of percentages
#' @param digits number of digits to round large percentages (i.e. greater than 10%).
#' Smaller percentages are rounded to `digits + 1` places.
#' Default is `0`
#' @param symbol Logical indicator to include percent symbol in output.
#' Default is `FALSE`.
#' @inheritParams style_number
#' @export
#' @return A character vector of styled percentages
#' @family style tools
#' @seealso See Table Gallery \href{https://www.danieldsjoberg.com/gtsummary/articles/gallery.html}{vignette} for example
#' @author Daniel D. Sjoberg
#' @examples
#' percent_vals <- c(-1, 0, 0.0001, 0.005, 0.01, 0.10, 0.45356, 0.99, 1.45)
#' style_percent(percent_vals)
#' style_percent(percent_vals, symbol = TRUE, digits = 1)
style_percent <- function(x, symbol = FALSE, digits = 0, big.mark = NULL, decimal.mark = NULL, ...) {
  y <- dplyr::case_when(
    x * 100 >= 10 ~ style_number(x * 100, digits = digits, big.mark = big.mark, decimal.mark = decimal.mark, ...),
    x * 100 >= 10^(-(digits + 1)) ~ style_number(x * 100, digits = digits + 1, big.mark = big.mark, decimal.mark = decimal.mark, ...),
    x > 0 ~ paste0("<", style_number(
      x = 10^(-(digits + 1)), digits = digits + 1, big.mark = big.mark,
      decimal.mark = decimal.mark, ...
    )),
    x == 0 ~ "0"
  )

  # adding percent symbol if requested
  if (symbol == TRUE) y <- ifelse(!is.na(y), paste0(y, "%"), y)
  attributes(y) <- attributes(unclass(x))
  return(y)
}