Deprecate validation_split()

[DavisVaughan]

This is a fairly confusing name because it doesn't produce a split object like initial_split() does. It produces a single resample object. Maybe it should be named validation_set(), or simply validation().

I think we could provide an alias for it with a better name and immediately deprecate the old name with lifecycle::deprecate_warn() (still works, but users get a warning once every session).

[mikemahoney218]

My only concern is that between the 1.0.0 release, TMwR publication, and workshops, it might be a bad time to deprecate one of the "main" functions from the package. But other than that I agree validation_set() is a better name.

[hfrick]

We have new functions to create and work with a validation split, following the mental model of a three-way split, rather than a sequence of two binary splits. The function to give you an rset is called validation_set() and we've decided to deprecate validation_split(), starting with the soft-deprecation level.

library(rsample)
data(ames, package = "modeldata")

# the initial split is the 3-way split
first_split <- initial_validation_split(ames)

# get rset for tuning from the 3-way split
rset_for_tuning <- validation_set(first_split)

# access to individual subsets from the initial split
ames_train <- training(first_split)
ames_val <- validation(first_split)
ames_test <- testing(first_split)

# access to individual subsets from the rset
ames_analysis <- analysis(rset_for_tuning$splits[[1]]) # same as training(first_split)
ames_assesment <- assessment(rset_for_tuning$splits[[1]]) # same as validation(first_split)

^{Created on 2023-04-28 with reprex v2.0.2}

[hfrick]

Additional documentation to check and update, if necessary

• vignettes
• tidymodels.org

TMwR can stay as is for now.

extratests should be updated now, if validation_split() is used in other packages (tune?) we'll update the packages as we go

[github-actions]

This issue has been automatically locked. If you believe you have found a related problem, please file a new issue (with a reprex: https://reprex.tidyverse.org) and link to this issue.