以特定格式打印数组中的元素

Question

我有以下两个数组

int a[]={1,2,3,4,5,6,7,8,9};

int b[]={4,2,3}

输出应为

b[0] has 4 so the first line of output should be  1,2,3,4 (from array a )
b[1] has 2 so the 2nd line of output should be 5,6  (from array a )
b[2] has 3 so the 3rd line of outout should be 7,8,9  (from array a )

输出应该是这样的

1,2,3,4
5,6
7,8,9

我正在尝试使用此代码，但无法正常工作

for(i=0;i<b[j];i++)
     {
        if(flag==false){
        System.out.print(a[i]);
        flag=true;
        }
        else
            System.out.print(" "+a[i]);
     }
     j=j+1;
          System.out.print("\n");

注意：数组a和b可以有任意数量的元素

Answer 1

int cur = 0;                                    //denotes index of array a
for (int i=0; i<b.length; i++) {                //looping on the elements of b

    int count = b[i], j;                       //count: number of elements to print is in b[i]
    for(j=cur; j<cur+count && j<a.length; j++) //looping from current index in array a to the next "count" elements which we need to print
       System.out.print(a[j]+",");             //print the elements for one line
    System.out.println();
    cur = j;                                  //updating the new index of array a from where to start printing  
}

Answer 2

通过将b[]元素的运行总计保存在整数变量nextIndex ，我们跟踪在a[]到达哪个索引。

注意：该代码起作用的前提条件是b[]的元素总和不得大于a[]的元素数。

public static void main(String[] args) {

    int[] a = { 1,2,3,4,5,6,7,8,9 };
    int[] b = { 4,2,3 };

    int nextIndex = 0;

    for (int i = 0; i < b.length; i++) {

        for (int j = nextIndex; j < nextIndex + b[i]; j++) {

            if (j == (nextIndex + b[i] - 1)) {
                System.out.print(a[j]);
            }
            else {
                System.out.print(a[j] + ",");
            }

        }

        nextIndex += (b[i]);

        System.out.println();

    }
}

Answer 3

当使用Arrays.copyOfRange(int[] original, int from, int to)从原始数组中提取“子”数组时，一个for循环足以完成您想要的Arrays.copyOfRange(int[] original, int from, int to) 。 Arrays.toString()为您打印阵列。

public static void main(String[] args) throws Exception {
    int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
    int b[] = {4, 2, 3};

    int aIndex = 0;
    int bIndex = 0;
    for (int i = 0; i < b.length; i++) {
        bIndex += b[i]; // Keeps track of the ending index of the copying
        System.out.println(Arrays.toString(Arrays.copyOfRange(a, aIndex, bIndex)));
        aIndex += b[i]; // Keeps track of the starting index of the copying
    }
}

结果：

[1, 2, 3, 4]
[5, 6]
[7, 8, 9]