R/mlr_task_generators.R

In mllg/mlr3: Machine Learning in R - Next Generation

#' @title Dictionary of Task Generators
#'
#' @usage NULL
#' @format [R6::R6Class] object inheriting from [mlr3misc::Dictionary].
#'
#' @description
#' A simple [mlr3misc::Dictionary] storing objects of class [TaskGenerator].
#' Each task generator has an associated help page, see `mlr_task_generators_[id]`.
#'
#' This dictionary can get populated with additional task generators by add-on packages.
#'
#' For a more convenient way to retrieve and construct task generators, see [tgen()].
#'
#' @section Methods:
#' See [mlr3misc::Dictionary].
#'
#' @section S3 methods:
#' * `as.data.table(dict)`\cr
#'   [mlr3misc::Dictionary] -> [data.table::data.table()]\cr
#'   Returns a [data.table::data.table()] with fields `"key"` and `"packages"` as columns.
#'
#' @family Dictionary
#' @family TaskGenerator
#' @seealso
#' Example generators: [`xor`][mlr_task_generators_xor]
#'
#' Sugar function: [tgen()]
#' @export
#' @examples
#' mlr_task_generators$get("smiley")
#' tgen("2dnormals")
mlr_task_generators = R6Class("DictionaryTaskGenerator",
  inherit = Dictionary,
  cloneable = FALSE
)$new()

#' @export
as.data.table.DictionaryTaskGenerator = function(x, ...) {
  setkeyv(map_dtr(x$keys(), function(key) {
    g = x$get(key)
    list(
      key = key,
      packages = list(g$packages))
  }), "key")[]
}