java实例--每日一练

求数组交集 

使用 retainAll () 方法来计算两个数组的交集：

mport java.util.ArrayList;
public class 数组交集 {
    public static void main(String[] args) {
        ArrayList array1=new ArrayList();
        ArrayList array2=new ArrayList();
        array1.add(0,"english");
        array1.add(1,"chinese");
        array1.add(2,"french");
        array2.add(0,"english");
        array2.add(1,"can't chinese");
        array2.add(2,"can't french");
        System.out.println("arrary1 数组元素:"+array1);
        System.out.println("array2 数组元素:"+array2);
        array1.retainAll(array2);
        System.out.println("array2 & array1 数组交集为："+array1);
    }
}

结果如下：
arrary1 数组元素:[english, chinese, french]
array2 数组元素:[english, can't chinese, can't french]
array2 & array1 数组交集为：[english]