R/simple.R

In twolodzko/misster: Simple tools for dealing with missing values

#' Replace missing values with a constant
#'
#' @param x        a vector.
#' @param value    scalar used as a replacement value.
#' @param trim     the fraction (0 to 0.5) of observations to be
#'                 trimmed from each end of x before the mean is
#'                 computed. Values of trim outside that range
#'                 are taken as the nearest endpoint. See
#'                 \code{\link{mean}}.
#'
#' @examples
#'
#' x <- c(NA, 1, 2, NA, 4, NA, NA, 7, NA)
#' na_mean(x)
#' na_median(x)
#' na_mode( c(2, 1, 2, NA, 4, NA, NA, 3, 2, 1, NA) )
#' na_mode( c( NA, "a", NA, "b", "a", NA, NA) )
#'
#' @importFrom stats median
#'
#' @export

na_const <- function(x, value = mean(x, na.rm = TRUE)) {
  if ( length(value) > 1L )
    message("value has length > 1 and only the first element will be used")
  nas <- is.na(x)
  x <- as_imputed(x)
  x[nas] <- value[1L]
  x
}

#' @rdname na_const
#' @export

na_mean <- function(x, trim = 0) {
  na_const(x, value = mean(x, trim = trim, na.rm = TRUE))
}

#' @rdname na_const
#' @export

na_median <- function(x) {
  na_const(x, value = median(x, na.rm = TRUE))
}

#' @rdname na_const
#' @export

na_mode <- function(x) {
  na_const(x, value = Mode(x, na.rm = TRUE))
}