ArrayList举例使用说明方法

public class HandleArrayList {


    public static void main(String[] args) {
        ArrayList<String> cityList = new ArrayList<>();

        cityList.add("suzhou");
        cityList.add("shanghai");
        cityList.add("beijing");
        cityList.add("hangzhou");
        cityList.add("nanning");
        cityList.add("chengdu");
        cityList.add("wuhan");
        System.out.println("List size?\t\t" + cityList.size());
        System.out.println("is taiwan in the list?\t\t" + cityList.contains("taiwan"));
        System.out.println("the location of shanghai in the list?\t\t" + cityList.indexOf("shanghai"));
        System.out.println("is the list empty?\t\t" + cityList.isEmpty());

        cityList.add("tianjin");

//        cityList.remove("wuhan");

        System.out.println(cityList.toString());

//        倒序打印
        for (int i = cityList.size() - 1; i >= 0; i--) {
            System.out.print(cityList.get(i) + "\t\t");
        }
        System.out.println();


        String[] names = {"red", "green", "blue"};
        ArrayList<String> list = new ArrayList<>(Arrays.asList(names));
        System.out.println(list.toString());
//排序

        Integer[] numbers = {34, 23, 56, 78, 98};
        ArrayList<Integer> num = new ArrayList<>(Arrays.asList(numbers));
        sort(num);
        sum(num);
//        Collections.sort(num);
//        System.out.println(num);

//        最值
        System.out.println("最大值:\t" + Collections.max(num));
        System.out.println("最小值:\t" + Collections.min(num));
        Collections.shuffle(num);
//随机打乱列表元素
        System.out.println("随机打乱列表元素:\t" + num);
//合并两个列表元素
        ArrayList<Integer> list01 = new ArrayList<>();
        list01.add(1);
        list01.add(2);
        list01.add(3);
        list01.add(4);
        list01.add(5);

        ArrayList<Integer> list02 = new ArrayList<>();
        list02.add(4);
        list02.add(5);
        list02.add(6);
        list02.add(7);

        ArrayList<Integer> mergedList = union(list01, list02);
        System.out.println("合并结果为:\t\t"+mergedList);

//去掉重复元素
        ArrayList<Integer> list03 = new ArrayList<>();
        list03.add(1);
        list03.add(2);
        list03.add(3);
        list03.add(4);
        list03.add(5);

        System.out.println("没有移除前的元素: " + list03);

        removeDuplicate(list03);

        System.out.println("重复元素移除后的元素: " + list03);




    }

    //    对ArrayLsit排序
    public static void sort(ArrayList<Integer> list) {
//
        System.out.println("ArrayList方式排顺序");
        Collections.sort(list);
        System.out.println(list);
    }

    //    对ArrayLsit求和
    public static void sum(ArrayList<Integer> list) {
        double sum=0;
        for (int i = 0; i < list.size(); i++) {
            sum+=list.get(i);
        }
        System.out.println("the sum is :\t"+sum);
    }

//    合并两个列表
    public static ArrayList<Integer> union(ArrayList list1,ArrayList list2){
        ArrayList<Integer> mergeGroup=new ArrayList<>(list1);
        mergeGroup.addAll(list2);
        return mergeGroup;
    }
//    去掉重复元素
    public static void removeDuplicate(ArrayList<Integer> list){
        HashSet<Integer> set = new HashSet<>(list);
        list.clear();
        list.addAll(set);
    }


}