Predict from a fitted CHAID tree

Routes the rows of newdata down the tree and returns predictions. Factor levels unseen during training, and codes that did not occur in a node when it was split, are routed to the child with the largest node size (for ordinal predictors, to the group with the smallest code distance); a warning is issued when unseen levels are detected.

Usage

# S3 method for class 'chaid'
predict(object, newdata, type = c("response", "prob", "node"), ...)

Arguments

object

A fitted "chaid" object returned by chaid().

newdata

A data frame containing all predictor variables used in the fit.

type

"response" (default) returns predicted classes (or means for a continuous response), "prob" returns a matrix of class probabilities (categorical responses only), "node" returns the terminal node id for each row.

...

Ignored.

Value

Depending on type: a factor (or numeric vector) of predictions, a numeric matrix of class probabilities with one column per response level, or an integer vector of node ids.

See also

chaid()

Examples

fit <- chaid(Species ~ ., data = iris,
             control = chaid_control(min_parent = 30, min_child = 10))
predict(fit, head(iris))
#> [1] setosa     setosa     setosa     setosa     setosa     versicolor
#> Levels: setosa versicolor virginica
predict(fit, head(iris), type = "prob")
#>         setosa versicolor virginica
#> [1,] 1.0000000  0.0000000         0
#> [2,] 1.0000000  0.0000000         0
#> [3,] 1.0000000  0.0000000         0
#> [4,] 1.0000000  0.0000000         0
#> [5,] 1.0000000  0.0000000         0
#> [6,] 0.4285714  0.5714286         0
predict(fit, head(iris), type = "node")
#> [1] 2 2 2 2 2 3