R/roundBy.R

In twolodzko/twextras: twextras

#' Round numbers by a specyfic value
#' 
#' @param x         numeric vector.
#' @param by        rounding value.
#' @param roundUp   if \code{TRUE} then categories are rounded up.
#' @param symmetric if \code{TRUE} then categories are symmetric around zero
#'                  (rather than rounded up or down).
#' @examples 
#' 
#' x <- seq(-5, 5, by = 0.5)
#' rbind(roundBy(x, roundUp = F, symmetric = F),
#'       roundBy(x, roundUp = T, symmetric = F),
#'       roundBy(x, roundUp = F, symmetric = T),
#'       roundBy(x, roundUp = T, symmetric = T))
#'                           
#' @export


roundBy <- function(x, by = 1, roundUp = FALSE, symmetric = FALSE) {
  sgn <- if (symmetric) sign(x) else 1
  if (roundUp) ceiling(x*sgn/by)*by*sgn
  else floor(x*sgn/by)*by*sgn
}