S3 method to convert hardhat format to numeric

Author: topepo

NAMESPACE

@@ -1,6 +1,9 @@
 # Generated by roxygen2: do not edit by hand
 
 S3method(augment,model_fit)
+S3method(convert_case_weights,default)
+S3method(convert_case_weights,hardhat_frequency_weights)
+S3method(convert_case_weights,hardhat_importance_weights)
 S3method(extract_fit_engine,model_fit)
 S3method(extract_parameter_dials,model_spec)
 S3method(extract_parameter_set_dials,model_spec)
@@ -178,6 +181,7 @@ export(check_model_doesnt_exist)
 export(check_model_exists)
 export(contr_one_hot)
 export(control_parsnip)
+export(convert_case_weights)
 export(convert_stan_interval)
 export(ctree_train)
 export(cubist_rules)

R/case_weights.R

@@ -28,6 +28,7 @@
 #' @seealso [frequency_weights()], [importance_weights()], [fit()], [fit_xy]
 NULL
 
+# ------------------------------------------------------------------------------
 
 weights_to_numeric <- function(x, spec) {
   if (is.null(x)) {
@@ -46,6 +47,51 @@ weights_to_numeric <- function(x, spec) {
   x
 }
 
+#' Convert case weights to final from
+#'
+#' tidymodels requires case weights to have special classes. To use them in
+#' model fitting or performance evaluation, they need to be converted to
+#' numeric.
+#' @param x A vector with class `"hardhat_case_weights"`.
+#' @param where The location where they will be used: `"parsnip"` or
+#' `"yardstick"`.
+#' @return A numeric vector or NULL.
+#' @export
+convert_case_weights <- function(x, where = "parsnip", ...) {
+  UseMethod("convert_case_weights")
+}
+
+#' @export
+convert_case_weights.default <- function(x, where = "parsnip", ...) {
+  where <- rlang::arg_match0(where, c("parsnip", "yardstick"))
+  if (!inherits(x, "hardhat_case_weights")) {
+    rlang::abort("'case_weights' should be  vector of class 'hardhat_case_weights'")
+  }
+  invisible(NULL)
+}
+
+#' @export
+#' @rdname convert_case_weights
+convert_case_weights.hardhat_importance_weights <-
+  function(x, where = "parsnip", ...) {
+    if (where == "parsnip") {
+      x <- as.double(x)
+    } else {
+      x <- NULL
+    }
+    x
+  }
+
+#' @export
+#' @rdname convert_case_weights
+convert_case_weights.hardhat_frequency_weights <-
+  function(x, where = "parsnip", ...) {
+    as.integer(x)
+  }
+
+
+# ------------------------------------------------------------------------------
+
 case_weights_allowed <- function(spec) {
   mod_type <- class(spec)[1]
   mod_eng <- spec$engine

man/convert_case_weights.Rd

@@ -17,5 +17,6 @@ StripTrailingWhitespace: Yes
 
 BuildType: Package
 PackageUseDevtools: Yes
+PackageCleanBeforeInstall: Yes
 PackageInstallArgs: --no-multiarch --with-keep.source
 PackageRoxygenize: rd,collate,namespace