Example: ZeroR (Majority Class)

public class ZeroR extends DistributionClassifier implements WeightedInstancesHandler {

private double m_ClassValue; //The class value 0R predicts

private double [] m_Counts; //The number of instances in each class

public void buildClassifier(Instances instances) throws Exception {

m_Counts = new double [instances.numClasses()];

for (int i = 0; i < m_Counts.length; i++) { //Initialize counts

m_Counts[i] = 1;

}

Enumeration enum = instances.enumerateInstances();

while (enum.hasMoreElements()) { //Add up class counts

Instance instance = (Instance) enum.nextElement();

m_Counts[(int)instance.classValue()] += instance.weight();

}

m_ClassValue = Utils.maxIndex(m_Counts); //Find majority class

Utils.normalize(m_Counts); } //Normalize counts

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