将所有值分配给整个数组[重复]

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这个问题在这里已有答案:

How do I fill arrays in Java? 8 answers

如何在Java中填充数组? 8个答案

I am writing a Java program and I am using the following code for assigning some variables to an array:

我正在编写一个Java程序,我使用以下代码将一些变量分配给一个数组:

for(int j=1;j<P.maxNetworkPow;j++){
    node.succList[j]=node.succ.succList[j-1];
}

Who knows how can I assign the all values to the array without for loop?

谁知道如何在没有for循环的情况下将所有值分配给数组?

3 个解决方案

#1

Use Arrays.fill(node.succList, value) javadoc. If you want to fill array with one value.

使用Arrays.fill(node.succList,value)javadoc。如果要使用一个值填充数组。

If you want to init array from the other one use

如果你想从另一个使用init数组

System.arraycopy(Object src, int srcPos, Object dest, int destPos, int length) javadoc

System.arraycopy(Object src,int srcPos,Object dest,int destPos,int length)javadoc

#2

Use System.arraycopy. Example as follows:

使用System.arraycopy。示例如下:

import java.lang.*;

public class SystemDemo {

   public static void main(String[] args) {

   int arr1[] = { 0, 1, 2, 3, 4, 5 };
   int arr2[] = { 5, 10, 20, 30, 40, 50 };

   // copies an array from the specified source array
   System.arraycopy(arr1, 0, arr2, 0, 1);
   System.out.print("array2 = ");
   System.out.print(arr2[0] + " ");
   System.out.print(arr2[1] + " ");
   System.out.print(arr2[2] + " ");
   System.out.print(arr2[3] + " ");
   System.out.print(arr2[4] + " ");
   }
}

will output: array2 = 0 10 20 30 40

将输出:array2 = 0 10 20 30 40

#3

As user khelwood pointed out, you can use System.arraycopy to copy elements of a specific range from one array to another.

用户khelwood指出,您可以使用System.arraycopy将特定范围的元素从一个数组复制到另一个数组。

The method signature is:

方法签名是:

public static void arraycopy(Object src, int srcPos, Object dest, int destPos, int length)

src is the source array which you want to copy

src是您要复制的源数组

srcPos is the starting position in the source array

srcPos是源数组中的起始位置

dest is the destination array you want to copy the data to

dest是要将数据复制到的目标数组

destPos is the starting position in the destination array

destPos是目标数组中的起始位置

length is the number of array elements copied

length是复制的数组元素的数量

For your case, it would be

对于你的情况,它会

System.arraycopy(node.succ.succList, 0, node.succList, 1, P.maxNetworkPow - 1);

Which means copy P.maxNetworkPow - 1 elements from node.succ.succList at starting index 0 to the array node.succList at starting index 1.

这意味着将P.maxNetworkPow - 从起始索引0处的node.succ.succList中的1个元素复制到起始索引1处的数组node.succList。

You have to be careful though, that P.maxNetworkPow is not bigger than the length of each array, or else you'll get an IndexOutOfBoundsException

你必须要小心,P.maxNetworkPow不大于每个数组的长度,否则你将获得IndexOutOfBoundsException

#1