JAVA单排日记-2019/10/16-2-数组工具类Arrays

• 简介
  Arrays提供了大量的静态方法，用来实现常用的数组操作
• 使用

1. 将数组按照默认格式变成字符串

String str = Arrys.toString(数组);

package day1017;

import java.util.Arrays;

public class DemoArrays {
    public static void main(String[] args) {
        int[] a = {1,2,3,4};
        String str = Arrays.toString(a);
        System.out.println(str); //[1,2,3,4]
    }
}

2. 按照默认升序对数组元素排序

Arrys.sort(数组);

package day1017;

import java.util.Arrays;

public class DemoArrays {
    public static void main(String[] args) {
        int[] a = {3,42,3,5,2,0,6};
        Arrays.sort(a);
        System.out.println(Arrays.toString(a));
    }
}

练习

package day1017;

import java.util.Arrays;

public class Demotr {
    public static void main(String[] args) {
        String str = "asdqwdq798712kjad23asdhi287yajkcxzmiu2";
        char[] a = str.toCharArray();
        Arrays.sort(a);
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[a.length-1-i]);
        }

    }
}