代码-Weka的决策树类J48

package kit.weka; 

/** 

* desc:试试Weka的决策树类 

* <code>J48Test</code> 

* 

*/  

import java.io.File;  

import java.io.IOException;  

import weka.classifiers.Classifier;  

import weka.classifiers.trees.J48;  

import weka.core.Instances;  

import weka.core.converters.ArffLoader;  

public class J48Test {  

    /** 

     * @param args 

     * @throws Exception  

     */  

    public static void main(String[] args) throws Exception {  

         Classifier m_classifier = new J48();  

            File inputFile = new File("d:\\Program Files\\Weka-3-7\\data\\cpu.with.vendor.arff");//训练语料文件  

            ArffLoader atf = new ArffLoader();   

            atf.setFile(inputFile);  

            Instances instancesTrain = atf.getDataSet(); // 读入训练文件      

            inputFile = new File("d:\\Program Files\\Weka-3-7\\data\\cpu.with.vendor.arff");//测试语料文件  

            atf.setFile(inputFile);            

            Instances instancesTest = atf.getDataSet(); // 读入测试文件  

            instancesTest.setClassIndex(0); //设置分类属性所在行号（第一行为0号），instancesTest.numAttributes()可以取得属性总数  

            double sum = instancesTest.numInstances(),//测试语料实例数  

            right = 0.0f;  

            instancesTrain.setClassIndex(0);  

             m_classifier.buildClassifier(instancesTrain); //训练             

            for(int  i = 0;i<sum;i++)//测试分类结果  

            {  

                if(m_classifier.classifyInstance(instancesTest.instance(i))==instancesTest.instance(i).classValue())//如果预测值和答案值相等（测试语料中的分类列提供的须为正确答案，结果才有意义）  

                {  

                  right++;//正确值加1  

                }  

            }  

            System.out.println("J48 classification precision:"+(right/sum));  

    }  

}  

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }