Classification rate Weka Java API

Question

I would like to get the classification rate for a tree constructed using J48.

DataSource source = new DataSource(Path);
Instances data = source.getDataSet();
J48 tree = tree.buildClassifier(data);

I know it has something to do with

public double getMeasure(java.lang.String additionalMeasureName)

But i can't find the correct String (additionalMeasureName) to use.

Answer 1

I just found an answer to my question using Evaluation class. The code should be:

//Learning
DataSource source = new DataSource(Path);
Instances data = source.getDataSet();
J48 tree = new J48();
tree.buildClassifier(data);

//Evaluation
Evaluation eval = new Evaluation(data);
eval.evaluateModel(tree, data);
System.out.println((eval.correct()/data.numInstances())*100);

This tests the decision tree using the learning data an displays the percentage of correctly classified instances.