Render a CHAID tree as Graphviz DOT

chaid_dot() generates a publication-quality Graphviz DOT description of the tree using base R only. It can be rendered with chaid_graphviz() (which uses 'DiagrammeR', bundling viz.js so no Graphviz binary is needed) or written to a .gv file and rendered externally with dot -Tpng / dot -Tsvg.

Usage

chaid_dot(
  fit,
  palette = NULL,
  rankdir = "TB",
  label_len = 28,
  legend = TRUE,
  file = NULL
)

# S3 method for class 'chaid_dot'
print(x, ...)

chaid_graphviz(fit, ...)

Arguments

fit

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

palette

Vector of class colours for categorical responses (default grDevices::hcl.colors(n, "Dark 3"), matching plot.chaid()). For continuous responses node fills use a white-to-steelblue gradient of the node means.

rankdir

Graph direction: "TB" (top to bottom, default) or "LR" (left to right).

label_len

Maximum number of characters for edge (split group) labels.

legend

Logical. Add a legend node with the class colours (categorical responses only).

file

Optional path; when given, the DOT source is also written there in UTF-8 for use with the external dot command.

x

A "chaid_dot" object.

...

For chaid_graphviz(), arguments passed on to chaid_dot(); ignored by print().

Value

For chaid_dot(), the DOT source as a character string of class "chaid_dot" (returned invisibly; its print() method outputs the source). For chaid_graphviz(), an 'htmlwidget' as returned by DiagrammeR::grViz().

See also

plot.chaid(), chaid_plotly()

Examples

fit <- chaid(Species ~ ., data = iris,
             control = chaid_control(min_parent = 30, min_child = 10))
dot <- chaid_dot(fit)