workflows (version 0.2.1)

workflow-extractors: Extract elements of a workflow

Description

These functions extract various elements from a workflow object. If they do not exist yet, an error is thrown.

• pull_workflow_preprocessor() returns the formula, recipe, or variable expressions used for preprocessing.

• pull_workflow_spec() returns the parsnip model specification.

• pull_workflow_fit() returns the parsnip model fit.

• pull_workflow_mold() returns the preprocessed "mold" object returned from hardhat::mold(). It contains information about the preprocessing, including either the prepped recipe or the formula terms object.

• pull_workflow_prepped_recipe() returns the prepped recipe. It is extracted from the mold object returned from pull_workflow_mold().

Usage

pull_workflow_preprocessor(x)
pull_workflow_spec(x)
pull_workflow_fit(x)
pull_workflow_mold(x)
pull_workflow_prepped_recipe(x)

Arguments

x

A workflow

Value

The extracted value from the workflow, x, as described in the description section.

Examples

# NOT RUN {
library(parsnip)
library(recipes)
library(magrittr)

model <- linear_reg() %>%
  set_engine("lm")

recipe <- recipe(mpg ~ cyl + disp, mtcars) %>%
  step_log(disp)

base_wf <- workflow() %>%
  add_model(model)

recipe_wf <- add_recipe(base_wf, recipe)
formula_wf <- add_formula(base_wf, mpg ~ cyl + log(disp))
variable_wf <- add_variables(base_wf, mpg, c(cyl, disp))

fit_recipe_wf <- fit(recipe_wf, mtcars)
fit_formula_wf <- fit(formula_wf, mtcars)

# The preprocessor is a recipes, formula, or a list holding the
# tidyselect expressions identifying the outcomes/predictors
pull_workflow_preprocessor(recipe_wf)
pull_workflow_preprocessor(formula_wf)
pull_workflow_preprocessor(variable_wf)

# The `spec` is the parsnip spec before it has been fit.
# The `fit` is the fit parsnip model.
pull_workflow_spec(fit_formula_wf)
pull_workflow_fit(fit_formula_wf)

# The mold is returned from `hardhat::mold()`, and contains the
# predictors, outcomes, and information about the preprocessing
# for use on new data at `predict()` time.
pull_workflow_mold(fit_recipe_wf)

# A useful shortcut is to extract the prepped recipe from the workflow
pull_workflow_prepped_recipe(fit_recipe_wf)

# That is identical to
identical(
  pull_workflow_mold(fit_recipe_wf)$blueprint$recipe,
  pull_workflow_prepped_recipe(fit_recipe_wf)
)
# }

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