step_collapse: Collapse Predictors into a single list-column

In kerasnip: A Bridge Between 'keras' and 'tidymodels'

Collapse Predictors into a single list-column

Description

step_collapse() creates a a specification of a recipe step that will convert a group of predictors into a single list-column. This is useful for custom models that need the predictors in a different format.

Usage

step_collapse(
  recipe,
  ...,
  role = "predictor",
  trained = FALSE,
  columns = NULL,
  new_col = "predictor_matrix",
  skip = FALSE,
  id = recipes::rand_id("collapse")
)

Arguments

recipe	A recipe object. The step will be added to the sequence of operations for this recipe.
...	One or more selector functions to choose which variables are affected by the step. See ⁠[selections()]⁠ for more details. For the tidy method, these are not currently used.
role	For model terms created by this step, what analysis role should they be assigned?. By default, the new columns are used as predictors.
trained	A logical to indicate if the quantities for preprocessing have been estimated.
columns	A character string of the selected variable names. This is NULL until the step is trained by ⁠[prep.recipe()]⁠.
new_col	A character string for the name of the new list-column. The default is "predictor_matrix".
skip	A logical. Should the step be skipped when the recipe is baked by ⁠[bake.recipe()]⁠? While all operations are baked when prep is run, skipping when bake is run may be other times when it is desirable to skip a processing step.
id	A character string that is unique to this step to identify it.

Value

An updated version of recipe with the new step added to the sequence of existing steps (if any). For the tidy method, a tibble with columns terms which is the columns that are affected and value which is the type of collapse.

Examples

library(recipes)

# 2 predictors
dat <- data.frame(
  x1 = 1:10,
  x2 = 11:20,
  y = 1:10
)

rec <- recipe(y ~ ., data = dat) %>%
  step_collapse(x1, x2, new_col = "pred") %>%
  prep()

bake(rec, new_data = NULL)

kerasnip documentation built on Nov. 5, 2025, 7:32 p.m.