R/impute_missing.R

In jazznbass/scaledic: Functions and data frame extension for scale based operations

#' Impute missing values
#'
#' @param data A data frame
#' @param filter A logical expression for any dic attribute (e.g. scale ==
#'   "ITRF" & subscale == "Int")
#' @param force_to_scale If TRUE, imputed values will be rounded and forced to
#'   the scale. That is, a value below the scale's minimum or maximum will be
#'   set to the scale's minimum and maximum.
#'
#' @return A data frame with imputed data.
#' @export
impute_missing <- function(data,
                           filter = NULL,
                           force_to_scale = TRUE) {

  filter <- deparse(substitute(filter))
  .impute_missing(data, filter, force_to_scale)
}

.impute_missing <- function(data, filter, force_to_scale = TRUE) {

  id <- .get_index(data, filter, class = "item")
  if (!any(is.na(data[, id]))) {
    message("No missing data.\n")
    return(data)
  }
  cl <- class(data)
  data[, id] <- Amelia::amelia(as.data.frame(data[, id]), boot.type = "none", m = 1)$imputations[[1]]
  class(data) <- cl

  if (force_to_scale) {
    for (i in id) {
      type <- dic_attr(data[[i]], .opt$type)
      values <- dic_attr(data[[i]], .opt$values)
      if (!(type %in% c("integer", "float", "real", "numeric", "double")) || is.null(values)) next
      x <- data[[i]]
      max_values <- max(values)
      min_values <- min(values)
      if (type %in% c("integer")) x[] <- round(x)
      x[] <- ifelse(x > max_values, max_values, x)
      x[] <- ifelse(x < min_values, min_values, x)
      data[, i] <- x
    }
  }
  data
}