Merge pull request #1232 from tidymodels/fix-tidy.step_cut

NEWS.md

@@ -4,6 +4,8 @@
 
 * Documentation for tidy methods for all steps has been added when missing and improved to describe the return value more accurately. (#936)
 
+* Fixed bug where `tidy.step_cut()` always returned zero row tibbles for trained recipes. (#1229)
+
 * It is now documented that `step_spline_b()` can be made periodic. (#1223)
 
 # recipes 1.0.8

R/cut.R

@@ -26,7 +26,7 @@
 #'
 #' \describe{
 #'   \item{terms}{character, the selectors or variables selected}
-#'   \item{value}{character, the location of the cuts}
+#'   \item{value}{numeric, the location of the cuts}
 #'   \item{id}{character, id of this step}
 #' }
 #'
@@ -217,17 +217,14 @@ print.step_cut <-
 #' @export
 tidy.step_cut <- function(x, ...) {
   if (is_trained(x)) {
-    values <- vapply(
-      unname(x$class_list),
-      FUN = function(x) paste0(x, collapse = "-"),
-      FUN.VALUE = character(1)
+    res <- tibble(
+      terms = rep(names(x$breaks), lengths(x$breaks)),
+      value = unlist(x$breaks, use.names = FALSE) %||% double()
     )
-
-    res <- tibble(terms = names(x$breaks), value = values)
   } else {
     term_names <- sel2char(x$terms)
-    res <- tibble(terms = term_names, value = na_chr)
+    res <- tibble(terms = term_names, value = na_dbl)
   }
-  res$id <- x$id
+  res$id <- rep(x$id, nrow(res))
   res
 }

tests/testthat/test-cut.R

@@ -148,6 +148,26 @@ test_that("step_cut integration test", {
   )
 })
 
+test_that("tidy method works", {
+  rec <- recipe(~., data = mtcars) %>%
+    step_cut(disp, hp, breaks = 200) %>%
+    prep()
+
+  res <- tidy(rec, 1)
+
+  expect_identical(
+    rep(c("disp", "hp"), each = 3),
+    res$terms
+  )
+
+  expect_identical(
+    c(min(mtcars$disp), 200, max(mtcars$disp),
+      min(mtcars$hp), 200, max(mtcars$hp)),
+    res$value
+  )
+})
+
+
 # Infrastructure ---------------------------------------------------------------
 
 test_that("bake method errors when needed non-standard role columns are missing", {
@@ -194,7 +214,7 @@ test_that("empty selection tidy method works", {
   rec <- recipe(mpg ~ ., mtcars)
   rec <- step_cut(rec, breaks = 5)
 
-  expect <- tibble(terms = character(), value = character(), id = character())
+  expect <- tibble(terms = character(), value = double(), id = character())
 
   expect_identical(tidy(rec, number = 1), expect)