HashSet 常用操作

import java.util.HashSet;
import java.util.Iterator;
import java.util.Random;

public class test {

    public static void main(String[] args) {
        //1.Set去重特性
        HashSet<String> hs = new HashSet<String>();
        hs.add("a");
        hs.add("b");
        hs.add("n");
        hs.add("1");
        hs.add("1");
        System.out.println(hs);

        //2.Set迭代遍历操作
        Iterator it = hs.iterator();
        while (it.hasNext()) {
            System.out.print(it.next());
        }
        System.out.println("");

        //3.Set的foreach遍历操作
        for (String str : hs) {
            System.out.print(str);
        }
        System.out.println("");
        
        //4.利用Set产生10个不同的数
        Random R =new Random();
        HashSet<Integer> hs1 = new HashSet<Integer>();
        while(hs1.size()<10){
            int res =  R.nextInt(20)+1;
            hs1.add(res);
        }
        System.out.println(hs1);
    }
}

 输出结果：

[a, 1, b, n]
a1bn
a1bn
[16, 18, 19, 3, 5, 6, 7, 8, 10, 13]