同学很久以前做的，那时候我刚实习，他刚参加工作（他是两年制），那时候开始对数据挖掘感兴趣，他发给我的他自己做的demo。记得他要毕业时，还一起帮着想kmeans创新点，如今他已经从事数据挖掘工作两年了。
他的博客地址：http://www.cnblogs.com/niuxiaoha/p/4645989.html
package neugle.kmeans;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
public class Kmeans {
private static int k = 3;// 划分簇数目
private static int dataCount = 150;// 文本数量
private static int n = 0;// 迭代次数
public static void main(String[] args) {
ArrayList<IrisModel> irisList = ReadFile();// 取得文本中数据
ArrayList<IrisModel> beforeRandomPot = new ArrayList<IrisModel>();// 记录上一次质心位置
ArrayList<IrisModel> randomPot = RandomPot(irisList);// 获得随机数据
ArrayList<ArrayList<IrisModel>> kMeansList = null;
while (!CompareRandomPot(beforeRandomPot, randomPot)) {
kMeansList = KMeans(irisList, randomPot);// 进行n次聚类
n++;
}
Print(kMeansList);
System.out.println("迭代了" + n + "次");
}
// 读取文件中数据
private static ArrayList<IrisModel> ReadFile() {
FileReader read = null;
BufferedReader br = null;
ArrayList<IrisModel> irisList = new ArrayList<IrisModel>();
try {
read = new FileReader("D:\\iris.data");
br = new BufferedReader(read);
String readLine = null;
while ((readLine = br.readLine()) != null) {
IrisModel iris = new IrisModel();
String[] agrs = readLine.split(",");
iris.Sep_len = Double.parseDouble(agrs[0]);
iris.Sep_wid = Double.parseDouble(agrs[1]);
iris.Pet_len = Double.parseDouble(agrs[2]);
iris.Pet_wid = Double.parseDouble(agrs[3]);
iris.Iris_type = agrs[4];
irisList.add(iris);
}
} catch (FileNotFoundException e) {
System.out.println("读取文件异常");
irisList = null;
} catch (IOException e) {
System.out.println("读取文件异常");
irisList = null;
} finally {
try {
br.close();
} catch (IOException e) {
System.out.println("关闭文件异常");
}
}
return irisList;
}
// 随机生成初始k个点
private static ArrayList<IrisModel> RandomPot(ArrayList<IrisModel> irisList) {
ArrayList<Integer> initCenter = new ArrayList<Integer>();
ArrayList<IrisModel> randomPot = new ArrayList<IrisModel>();
for (int i = 0; i < k; i++) {
int num = (int) (Math.random() * dataCount);
if (!initCenter.contains(num))
initCenter.add(num);
else
i--;
}
Iterator<Integer> i = initCenter.iterator();
while (i.hasNext()) {
randomPot.add(irisList.get(i.next()));
}
return randomPot;
}
// KMeans主程序
private static ArrayList<ArrayList<IrisModel>> KMeans(
ArrayList<IrisModel> irisList, ArrayList<IrisModel> randomPot) {
ArrayList<ArrayList<IrisModel>> groupNum = new ArrayList<ArrayList<IrisModel>>();
for (int i = 0; i < randomPot.size(); i++) {
ArrayList<IrisModel> list = new ArrayList<IrisModel>();
list.add(randomPot.get(i));
groupNum.add(list);
}
for (int i = 0; i < irisList.size(); i++) {
double temp = Double.MAX_VALUE;
int flag = -1;
for (int j = 0; j < randomPot.size(); j++) {
double distance = DistanceOfTwoPoint(irisList.get(i),
randomPot.get(j));
if (distance < temp) {
temp = distance;
flag = j;
}
}
groupNum.get(flag).add(irisList.get(i));
}
// 重新计算质心
ArrayList<IrisModel> tempList = CalcCenter(groupNum);
randomPot.clear();
for (int i = 0; i < tempList.size(); i++) {
randomPot.add(tempList.get(i));
}
return groupNum;
}
// 计算两点欧氏距离
private static double DistanceOfTwoPoint(IrisModel d1, IrisModel d2) {
double sum = Math.sqrt(Math.pow((d1.Sep_len - d2.Sep_len), 2)
+ Math.pow((d1.Sep_wid - d2.Sep_wid), 2)
+ Math.pow((d1.Pet_len - d2.Pet_len), 2)
+ Math.pow((d1.Pet_wid - d2.Pet_wid), 2));
return sum;
}
// 重新计算k个簇的质心
private static ArrayList<IrisModel> CalcCenter(
ArrayList<ArrayList<IrisModel>> c) {
ArrayList<IrisModel> cIris = new ArrayList<IrisModel>();
Iterator<ArrayList<IrisModel>> i = c.iterator();
while (i.hasNext()) {
ArrayList<IrisModel> irisList = i.next();
IrisModel eIris = new IrisModel();
for (int k = 0; k < irisList.size(); k++) {
eIris.Sep_len += irisList.get(k).Sep_len;
eIris.Sep_wid += irisList.get(k).Sep_wid;
eIris.Pet_len += irisList.get(k).Pet_len;
eIris.Pet_wid += irisList.get(k).Pet_wid;
}
eIris.Sep_len = eIris.Sep_len / irisList.size();
eIris.Sep_wid = eIris.Sep_wid / irisList.size();
eIris.Pet_len = eIris.Pet_len / irisList.size();
eIris.Pet_wid = eIris.Pet_wid / irisList.size();
cIris.add(eIris);
}
return cIris;
}
// 比较前后两次的质心，以确定是否结束
private static Boolean CompareRandomPot(
ArrayList<IrisModel> beforeRandomPot, ArrayList<IrisModel> randomPot) {
boolean flag = true;
for (int i = 0; i < randomPot.size(); i++) {
if (beforeRandomPot.size() <= 0
|| !beforeRandomPot.contains(randomPot.get(i))) {
flag = false;
break;
}
}
if (flag == false) {
if (beforeRandomPot.size() > 0) {
beforeRandomPot.clear();
}
for (int i = 0; i < randomPot.size(); i++) {
beforeRandomPot.add(randomPot.get(i));
}
}
return flag;
}
// 打印
private static void Print(ArrayList<ArrayList<IrisModel>> kmeansList) {
System.out.println("------------------------------------");
Iterator<ArrayList<IrisModel>> i = kmeansList.iterator();
while (i.hasNext()) {
Iterator<IrisModel> ii = i.next().iterator();
int n = 0;
while (ii.hasNext()) {
n++;
IrisModel irisModel = ii.next();
if (n == 1)
continue;
System.out.println(irisModel.Sep_len + " " + irisModel.Sep_wid
+ " " + irisModel.Pet_len + " " + irisModel.Pet_wid
+ " " + irisModel.Iris_type);
}
System.out.println(n - 1);
System.out.println("------------------------------------");
}
}
}