add scale and center functions

NAMESPACE

@@ -4,13 +4,15 @@ S3method(orbital,default)
 S3method(orbital,model_fit)
 S3method(orbital,model_spec)
 S3method(orbital,recipe)
+S3method(orbital,step_center)
 S3method(orbital,step_corr)
 S3method(orbital,step_filter_missing)
 S3method(orbital,step_lincomb)
 S3method(orbital,step_normalize)
 S3method(orbital,step_nzv)
 S3method(orbital,step_pca)
 S3method(orbital,step_rm)
+S3method(orbital,step_scale)
 S3method(orbital,step_select)
 S3method(orbital,step_zv)
 S3method(orbital,workflow)

R/step_center.R

@@ -0,0 +1,11 @@
+#' @export
+orbital.step_center <- function(x, all_vars, ...) {
+  means <- x$means
+
+  used_vars <- names(means) %in% all_vars
+  means <- means[used_vars]
+
+  out <- paste0(names(means), " - ", means)
+  names(out) <- names(means)
+  out
+}

R/step_scale.R

@@ -0,0 +1,11 @@
+#' @export
+orbital.step_scale <- function(x, all_vars, ...) {
+  sds <- x$sds
+
+  used_vars <- names(sds) %in% all_vars
+  sds <- sds[used_vars]
+
+  out <- paste0(names(sds) ," / ", sds)
+  names(out) <- names(sds)
+  out
+}

tests/testthat/test-step_center.R

@@ -0,0 +1,16 @@
+test_that("step_center works", {
+  skip_if_not_installed("recipes")
+
+  mtcars <- dplyr::as_tibble(mtcars)
+
+  rec <- recipes::recipe(mpg ~ ., data = mtcars) %>%
+    recipes::step_center(recipes::all_predictors()) %>%
+    recipes::prep()
+
+  res <- dplyr::mutate(mtcars, !!!orbital_inline(orbital(rec)))
+
+  exp <- recipes::bake(rec, new_data = mtcars)
+  exp <- exp[names(res)]
+
+  expect_equal(res, exp)
+})

tests/testthat/test-step_scale.R

@@ -0,0 +1,16 @@
+test_that("step_scale works", {
+  skip_if_not_installed("recipes")
+
+  mtcars <- dplyr::as_tibble(mtcars)
+
+  rec <- recipes::recipe(mpg ~ ., data = mtcars) %>%
+    recipes::step_scale(recipes::all_predictors()) %>%
+    recipes::prep()
+
+  res <- dplyr::mutate(mtcars, !!!orbital_inline(orbital(rec)))
+
+  exp <- recipes::bake(rec, new_data = mtcars)
+  exp <- exp[names(res)]
+
+  expect_equal(res, exp)
+})