Java实现的朴素贝叶斯算法示例
本文实例讲述了Java实现的朴素贝叶斯算法。分享给大家供大家参考,具体如下:
对于朴素贝叶斯算法相信做数据挖掘和推荐系统的小伙们都耳熟能详了,算法原理我就不啰嗦了。我主要想通过java代码实现朴素贝叶斯算法,思想:
1.用javabean+Arraylist对于训练数据存储
2.对于样本数据训练
具体的代码如下:
packageNB; /** *训练样本的属性javaBean * */ publicclassJavaBean{ intage; Stringincome; Stringstudent; Stringcredit_rating; Stringbuys_computer; publicJavaBean(){ } publicJavaBean(intage,Stringincome,Stringstudent,Stringcredit_rating,Stringbuys_computer){ this.age=age; this.income=income; this.student=student; this.credit_rating=credit_rating; this.buys_computer=buys_computer; } publicintgetAge(){ returnage; } publicvoidsetAge(intage){ this.age=age; } publicStringgetIncome(){ returnincome; } publicvoidsetIncome(Stringincome){ this.income=income; } publicStringgetStudent(){ returnstudent; } publicvoidsetStudent(Stringstudent){ this.student=student; } publicStringgetCredit_rating(){ returncredit_rating; } publicvoidsetCredit_rating(Stringcredit_rating){ this.credit_rating=credit_rating; } publicStringgetBuys_computer(){ returnbuys_computer; } publicvoidsetBuys_computer(Stringbuys_computer){ this.buys_computer=buys_computer; } @Override publicStringtoString(){ return"JavaBean[age="+age+",income="+income+",student=" +student+",credit_rating="+credit_rating+",buys_computer=" +buys_computer+"]"; } }
算法实现的部分:
packageNB; importjava.io.BufferedReader; importjava.io.File; importjava.io.FileReader; importjava.util.ArrayList; publicclassTestNB{ /**data_length *算法的思想 */ publicstaticArrayListlist=newArrayList ();; staticintdata_length=0; publicstaticvoidmain(String[]args){ //1.读取数据,放入list容器中 Filefile=newFile("E://test.txt"); txt2String(file); //数据测试样本 testData(25,"Medium","Yes","Fair"); } //读取样本数据 publicstaticvoidtxt2String(Filefile){ try{ BufferedReaderbr=newBufferedReader(newFileReader(file));//构造一个BufferedReader类来读取文件 Strings=null; while((s=br.readLine())!=null){//使用readLine方法,一次读一行 data_length++; splitt(s); } br.close(); }catch(Exceptione){ e.printStackTrace(); } } //存入ArrayList中 publicstaticvoidsplitt(Stringstr){ Stringstrr=str.trim(); String[]abc=strr.split("[\\p{Space}]+"); intage=Integer.parseInt(abc[0]); JavaBeanbean=newJavaBean(age,abc[1],abc[2],abc[3],abc[4]); list.add(bean); } //训练样本,测试 publicstaticvoidtestData(intage,Stringa,Stringb,Stringc){ //训练样本 intnumber_yes=0; intbumber_no=0; //age情况个数 intnum_age_yes=0; intnum_age_no=0; //income intnum_income_yes=0; intnum_income_no=0; //student intnum_student_yes=0; intnum_stdent_no=0; //credit intnum_credit_yes=0; intnum_credit_no=0; //遍历List获得数据 for(inti=0;i nb_buy_no){ System.out.println("新用户买的概率大"); }else{ System.out.println("新用户不买的概率大"); } } }
对于样本数据:
25 High No Fair No
25 High No Excellent No
33 High No Fair Yes
41 Medium No Fair Yes
41 Low YesFair Yes
41 Low YesExcellent No
33 Low YesExcellent Yes
25 Medium No Fair No
25 Low YesFair Yes
41 Medium YesFair Yes
25 Medium YesExcellent Yes
33 Medium No Excellent Yes
33 High YesFair Yes
41 Medium No Excellent No
对于未知用户的数据得出的结果:
购买的历史个数:9
不买的历史个数:5
购买+age:2
不买+age:3
购买+income:4
不买+income:2
购买+stundent:6
不买+student:1
购买+credit:6
不买+credit:2
训练数据中买的概率:0.6428571428571429
训练数据中不买的概率:0.35714285714285715
新用户买的概率:0.028218694885361547
新用户不买的概率:0.006857142857142858
新用户买的概率大
更多关于java算法相关内容感兴趣的读者可查看本站专题:《Java数据结构与算法教程》、《Java操作DOM节点技巧总结》、《Java文件与目录操作技巧汇总》和《Java缓存操作技巧汇总》
希望本文所述对大家java程序设计有所帮助。