Classification Tree Learner

A LearnerClassif for a classification tree implemented in rpart::rpart() in package rpart.

Initial parameter values

• Parameter xval is initialized to 0 in order to save some computation time.

Custom mlr3 parameters

• Parameter model has been renamed to keep_model.

Dictionary

This Learner can be instantiated via the dictionary mlr_learners or with the associated sugar function lrn():

mlr_learners$get("classif.rpart")
lrn("classif.rpart")

Meta Information

• Task type: “classif”

• Predict Types: “response”, “prob”

• Feature Types: “logical”, “integer”, “numeric”, “factor”, “ordered”

• Required Packages: mlr3, rpart

Parameters

Id	Type	Default	Levels	Range
cp	numeric	0.01		\([0, 1]\)
keep_model	logical	FALSE	TRUE, FALSE	-
maxcompete	integer	4		\([0, \infty)\)
maxdepth	integer	30		\([1, 30]\)
maxsurrogate	integer	5		\([0, \infty)\)
minbucket	integer	-		\([1, \infty)\)
minsplit	integer	20		\([1, \infty)\)
surrogatestyle	integer	0		\([0, 1]\)
usesurrogate	integer	2		\([0, 2]\)
xval	integer	10		\([0, \infty)\)

References

Breiman L, Friedman JH, Olshen RA, Stone CJ (1984). Classification And Regression Trees. Routledge. doi:10.1201/9781315139470 .

See also

• Chapter in the mlr3book: https://mlr3book.mlr-org.com/chapters/chapter2/data_and_basic_modeling.html#sec-learners

• Package mlr3learners for a solid collection of essential learners.

• Package mlr3extralearners for more learners.

• Dictionary of Learners: mlr_learners

• as.data.table(mlr_learners) for a table of available Learners in the running session (depending on the loaded packages).

• mlr3pipelines to combine learners with pre- and postprocessing steps.

• Package mlr3viz for some generic visualizations.

• Extension packages for additional task types:

  • mlr3proba for probabilistic supervised regression and survival analysis.

  • mlr3cluster for unsupervised clustering.

• mlr3tuning for tuning of hyperparameters, mlr3tuningspaces for established default tuning spaces.

Other Learner: Learner, LearnerClassif, LearnerRegr, mlr_learners, mlr_learners_classif.debug, mlr_learners_classif.featureless, mlr_learners_regr.debug, mlr_learners_regr.featureless, mlr_learners_regr.rpart

Super classes

mlr3::Learner -> mlr3::LearnerClassif -> LearnerClassifRpart

Methods

Public methods

• LearnerClassifRpart$new()

• LearnerClassifRpart$importance()

• LearnerClassifRpart$selected_features()

• LearnerClassifRpart$clone()

Inherited methods

• mlr3::Learner$base_learner()
• mlr3::Learner$configure()
• mlr3::Learner$encapsulate()
• mlr3::Learner$format()
• mlr3::Learner$help()
• mlr3::Learner$predict()
• mlr3::Learner$predict_newdata()
• mlr3::Learner$print()
• mlr3::Learner$reset()
• mlr3::Learner$train()

---

Method new()

Creates a new instance of this R6 class.

Usage

LearnerClassifRpart$new()

---

Method importance()

The importance scores are extracted from the model slot variable.importance.

Usage

LearnerClassifRpart$importance()

Returns

Named numeric().

---

Method selected_features()

Selected features are extracted from the model slot frame$var.

Usage

LearnerClassifRpart$selected_features()

Returns

character().

---

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerClassifRpart$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.