数组处理

import java.util.Arrays;

/**
 * @auther 付强
 * @date 2020/7/21 - 13:46
 */
public class java6 {
    public static void main(String[] args) {
        //一维数组
        int[] arr=new int[]{1,2,3,5,6};//还可以几种表现形式
        int []arr3=new int[5];
        arr3[0]=11;
        arr3[1]=10;//利用new分配内存时里面的元素初始值都是0;
        int arr2[]={1,5,3,5,8,5};
        String str=new String("12345");
        char[] arr1={'q','s','d'};
        String str1=new String(arr1);
        System.out.println(str);
        System.out.println(str1);
        int day[]=new int[]{31,28,30,40};
        for (int i = 0; i < day.length; i++) {
            System.out.println(day[i]);
        }
        //二维数组
        int []arr4[]=new int[3][4];
//        必须前边加一个，即必须行必须有数，否则报错，初始化后的值是0
        int [][]arr6=new int[6][4];
        for (int i = 0; i < arr6.length; i++) {
            for (int j = 0; j < arr6[i].length; j++) {
                System.out.print(arr6[i][j]);
            }
            System.out.println();//加入空格
        }
        int arr5[][]={{1,2,3},{54,9,5}};
        for (int i = 0; i < arr4.length; i++) {
            for (int j = 0; j < arr4[i].length; j++) {
                System.out.print(arr4[i][j]);
            }
            System.out.println();
        }
        for (int i = 0; i < arr5.length; i++) {
            for (int j = 0; j < arr5[i].length; j++) {
                System.out.print(arr5[i][j]+",");
            }
            System.out.println();
        }
        int arr7[][]={{1},{2,3},{4,5,6}};
        for (int i = 0; i < arr7.length; i++) {
            for (int j = 0; j < arr7[i].length; j++) {
                System.out.print(arr7[i][j]);
            }
            System.out.println();
        }
        int arr8[][]={{1,2},{3,4}};
        //进行打印1
        System.out.println("这个数组里面所包含的元素都有：");
        loop:
        for (int i = 0; i < arr8.length; i++) {
            for (int j = 0; j < arr8[i].length; j++) {
                System.out.print(arr8[i][j]);
                if(i==arr8.length-1&&j==arr8[0].length-1){
                    break loop;
                }else{
                    System.out.print(",");
                }
            }
        }
//        进行打印2
        System.out.println();
        int i=0;
        for(int arr9[]:arr8){
            int j=0;
            for(int arr10:arr9){
                if(i==arr8.length-1&&j==arr9.length-1){
                    System.out.print(arr8[i][j]);
                }else{
                    System.out.print(arr8[i][j]+",");
                }
                j++;
            }
            i++;
        }
        System.out.println();
//        数组元素覆盖，将一维数组全部覆盖为8
        int arr11[]=new int[8];
        Arrays.fill(arr11,8);
        System.out.println(Arrays.toString(arr11));
        Arrays.fill(arr11,1,5,6);
//        怎么说呢，将索引1到索引5的变成6，也就是说包头不包尾
        System.out.println(Arrays.toString(arr11));
        int arr12[]={1,8,3,58,6,58,9,6};
        Arrays.fill(arr12,2,6,12);
        System.out.println(Arrays.toString(arr12));
        Arrays.sort(arr12);
//      进行排序，然后求出结果
        System.out.println(Arrays.toString(arr12));
//        长度如果大于总长度的话会用0顶替，小于的话会被会从头截取，截取到这个长度结束
//        利用这种方式可以产生一个新的数组，利用复制的方式来获得新的数组
        int[] arr16 = Arrays.copyOf(arr, 4);
        
    }
}