R/apparent.R

In tidymodels/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 called 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 old sushi.
#'
#' @inheritParams vfold_cv
#' @return  A 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)
#' @export
apparent <- function(data, ...) {
  check_dots_empty()

  splits <- rsplit(data, in_id = seq_len(nrow(data)), out_id = seq_len(nrow(data)))

  class(splits) <- c("apparent_split", "rsplit")
  split_objs <- tibble::tibble(splits = list(splits), id = "Apparent")

  new_rset(
    splits = split_objs$splits,
    ids = split_objs$id,
    attrib = NULL,
    subclass = c("apparent", "rset")
  )
}