R/apparent.R

In topepo/rsample: General Resampling Infrastructure

#' Sampling for the Apparent Error Rate
#'
#' When building a model on a data set and re-predicting the same data, the
#'   performance estimate from those predictions is often call the 
#'   "apparent" performance of the model. This estimate can be wildly 
#'   optimistic. "Apparent sampling" here means that the analysis and 
#'   assessment samples are the same. These resamples are sometimes used in 
#'   the analysis of bootstrap samples and should otherwise be
#'   avoided like ol sushi. 
#'
#' @inheritParams vfold_cv
#' @return  An tibble with a single row and classes `apparent`, 
#'   `rset`, `tbl_df`, `tbl`, and `data.frame`. The 
#'   results include a column for the data split objects and one column 
#'   called `id` that has a character string with the resample identifier.
#' @examples
#' apparent(mtcars)
#' @importFrom purrr map
#' @export
apparent <- function(data, ...) {
  splits <- rsplit(data, in_id = 1:nrow(data), out_id = 1:nrow(data))
  # splits <- rm_out(splits)
  class(splits) <- c("rsplit", "apparent_split")
  split_objs <- tibble::tibble(splits = list(splits), id = "Apparent")
  
  split_objs <-
    add_class(split_objs,
              cls = c("apparent", "rset"),
              at_end = FALSE)
  
  split_objs
}

#' @export
print.apparent <- function(x, ...) {
  cat("#", pretty(x), "\n")
  class(x) <- class(x)[!(class(x) %in% c("apparent", "rset"))]
  print(x)
}