package lhy.core.util;

import java.util.Arrays;

import java.util.List;

public class ArraysTest {

    public static void main(String[] args) {

        int[] aa = {2,1,3,15,12,6}; 

        //1,数组转换成字符串:toString(int[] a)

        System.out.println(Arrays.toString(aa));//[1, 2, 3, 4, 5, 6]

        //2,复制指定的数组，截取或用 0 填充 copyOf(float[] original,int newLength)

        double[] dd = {4.1,6.2,3.4,9.6,8.8};

        double[] ddCopy = Arrays.copyOf(dd, 7);

        for (double d : ddCopy) {

            System.out.print(d + "  "); //4.1  6.2  3.4  9.6  8.8  0.0  0.0

        }

        System.out.println("\n复制数组指定范围到新数组：");

        //将指定数组的指定范围复制到一个新数组。

        int[] aaCopy = Arrays.copyOfRange(aa, 0, 3);

        for (int i : aaCopy) {

            System.out.print(i + "  ");//2  1  3

        }

        System.out.println("\n数组转list：");

        //3,数组转list

        String[] str = {"tom","jack","mashibing"};

        List<String> list = Arrays.asList(str);

        for (String string : list) {

            System.out.println(string);

        }

        System.out.println("快速排序sort:");

        //4,数组排序sort：快速排序

        Arrays.sort(aa);

        for (int a : aa) {

            System.out.print(a + "  "); //1  2  3  6  12  15

        }

        System.out.println("\n只排序数组指定下标部分：");

        //对指定下标部分 排序

        Arrays.sort(dd, 2, 4);

        for (double d : dd) {

            System.out.print(d +"  ");

        }

        System.out.println("\nbinarySearch二分查找：");

        //5：二分查找，必须先排序

        Arrays.sort(aa);

        int key = Arrays.binarySearch(aa, 4);

        if(key >= 0){//找到了key >= 0

            System.out.println("查找结果，key："+key+"  值为："+aa[key]);

        }else{

            System.out.println("数组中未查找到4，key:"+key); //数组中未查找到4，key:-4

        }

        //二分查找数组指定范围：

        key = Arrays.binarySearch(aa, 0, 3, 3);

        if(key >= 0){//找到了key >= 0

            System.out.println("查找结果，key："+key +" 值："+aa[key]); //查找结果，key：2 值：3

        }

        System.out.println("\n替换数组的值：");

        //6：替换数组的值

        int[] arr = new int[5];

        Arrays.fill(arr, 2);

        for (int i : arr) {

            System.out.print(i+"  "); //2  2  2  2  2

        }

        System.out.println("\n部分替换数组的值：");

        Arrays.fill(arr, 1, 3, 5);

        for (int i : arr) {

            System.out.print(i + "  ");//2  5  5  2  2

        }

        System.out.println("\n挨着比较2个数组值是否相等：");

        //7：比较2个数组是否相等

        int[] arr1 = {1,2,3,4};

        int[] arr2 = {2,1,3,4};

        System.out.println(Arrays.equals(arr1, arr2)); //false

    }

}