R/eda_re.R

In mgimond/tukeyedar: Tukey Inspired Exploratory Data Analysis Functions

#' @export
#' @title Re-expression function
#'
#' @description \code{eda_re} re-expresses a vector following the Tukey or
#' box-cox transformation.
#'
#' @param x Vector
#' @param p Power transformation
#' @param tukey If set to TRUE, then adopt Tukey's power transformation, if
#'   FALSE, adopt Box-Cox transformation
#'
#' @return Returns a vector of same length as input \code{x}
#'
#' @details The function is used to re-express data using one of two
#' transformation techniques: Box-Cox transformation (\code{tukey = FALSE})or
#' Tukey's power transformation (\code{tukey = TRUE}).
#'
#' @examples
#' x <- c(15, 28, 17, 73,  8, 83,  2)
#' eda_re(x, p=-1/3)

eda_re <- function(x, p=0, tukey=TRUE){
  if(p == 0) {
    z <- ifelse(!is.na(x), log(x), NA)
  } else if(tukey == FALSE & p != 1) {
    z <- ifelse(!is.na(x), (x^p - 1)/p , NA)
  } else {
    z <- ifelse(!is.na(x), x^p , NA)
  }
  return(z)
}