如何在给定范围内创建一个随机打乱数字的 int 数组

2022-01-14 00:00:00 arrays math random integer java

基本上，假设我有一个可以容纳 10 个数字的 int 数组.这意味着我可以在每个索引中存储 0-9(每个数字只能存储一次).

Basically, let's say I have an int array that can hold 10 numbers. Which mean I can store 0-9 in each of the index (each number only once).

如果我运行下面的代码:

If I run the code below:

int[] num = new int[10];
for(int i=0;i<10;i++){
    num[i]=i;
}

我的数组看起来像这样:

my array would look like this:

[0],[1],.....,[8],[9]

但是如何在每次运行代码时随机分配数字?例如，我希望数组看起来像:

But how do I randomize the number assignment each time I run the code? For example, I want the array to look something like:

[8],[1],[0].....[6],[3]

推荐答案

将其设为 List 而不是数组，并使用 Collections.shuffle() 对其进行随机播放.您可以在洗牌后从列表中构建 int[].

Make it a List<Integer> instead of an array, and use Collections.shuffle() to shuffle it. You can build the int[] from the List after shuffling.

如果你真的想直接进行随机播放，请搜索Fisher-Yates Shuffle".

If you really want to do the shuffle directly, search for "Fisher-Yates Shuffle".

以下是使用列表技术的示例:

Here is an example of using the List technique:

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Test {
  public static void main(String args[]) {
    List<Integer> dataList = new ArrayList<Integer>();
    for (int i = 0; i < 10; i++) {
      dataList.add(i);
    }
    Collections.shuffle(dataList);
    int[] num = new int[dataList.size()];
    for (int i = 0; i < dataList.size(); i++) {
      num[i] = dataList.get(i);
    }

    for (int i = 0; i < num.length; i++) {
      System.out.println(num[i]);
    }
  }
}

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