Java常用的Arrays函数举例详解

int[] array = new int[]{1,20,3};
Arrays.sort(array);// 1 3 20

int[] array = new int[]{1,2,3};
System.out.println(Arrays.toString(array));
// [1,2,3]

int[] array = new int[]{1,2,3};
System.out.println(Arrays.binarySearch(array,2));
// 返回1下标
// 第一个参数,有序的数组array,要查找的key

int[] array = new int[]{1,2,3};
int[] array1 = new int[]{1,3,2};
System.out.println(Arrays.equals(array,array1));
// false

int[] array = new int[10];
Arrays.fill(array,0,3,9);// [0,3)区间填充
Arrays.fill(array,9);// 都填充为9
System.out.println(Arrays.toString(array));

int[] array1 = new int[]{1,2,3};
int[] copy = Arrays.copyOf(array1,array1.length);
// 1 2 3 
// 可以当成扩容使用,剩余空间补零
int[] copy = Arrays.copyOf(array1,array1.length*2);
// 1 2 3 0 0 0

int[] array1 = new int[]{1,2,3,4,5,6};
int[] copy = Arrays.copyOfRange(array1,0,3);
// 1 2 3

int[] array1 = new int[]{1,2,3,4,5,6};
int[] copy = new int[array1.length];
System.out.println(array1,0,copy,0,array1.length);
System.out.println(Arrays.toString(copy));
// 1 2 3 4 5 6 

int[][] array = new int[][]{{1,2,3},{4,5,6}};
int[][] array1 = {{1,2,3},{4,5,6}};
int[][] array2 = new int[2][3];

for(int i = 0;i < array.length;i++){
	for(int j = 0;j < array[i].length;j++){
	       System.out.print(array[i][j] + " ");
	   }
	   System.out.println();
	}
System.out.println();

for(int[] arr : array1){
   for(int x : arr){
       System.out.print(x + " ");
   }
   System.out.println();
}

int[][] array1 = {{1,2,3},{4,5,6}};
System.out.println(Arrays.deepToString(array1));
// [[1, 2, 3], [4, 5, 6]]

int[][] array3 = new int[2][];

// 解决方法
array3[0] = new int[]{1,2};
array3[1] = new int[]{1,2,3};

System.out.println(array3[0]);
System.out.println(array3[1]);

for(int i = 0;i < array3.length;i++){
    for(int j = 0;j < array3[i].length;j++){
        System.out.print(array3[i][j] + " ");
    }
    System.out.println();
}