createBranch(predicate:attribute:)
Creates a child node that the decision tree should use when the current node’s attribute satisfies the specified predicate.
Declaration
func createBranch(predicate: NSPredicate, attribute: any NSObjectProtocol) -> SelfParameters
- predicate:
The predicate against which to test this node’s attribute.
- attribute:
The attribute for the child node to create.
Return Value
The newly created child node.
Discussion
Use this method to specify a possible result of testing this node’s attribute (that is, an answer for this node’s question). The attribute parameter an have either of two kinds of values: if this test produces the decision tree’s final result (or action), the value identifies that action; if the next step in the decision tree is to be another question, the value identifies the next attribute to test (or question to ask).
The predicate parameter is a predicate for testing values corresponding to this node’s attribute, so this method is useful for questions whose answers involve passing a threshold value, matching a substring, matching an element in a set, or some more complex test. (If a question has a few specific answer values, see the createBranch(value:attribute:) method instead.) For example, a strategy combat game might use this method to choose an attack based on the opponent’s health level: