如何返回5个随机“强力球”数字在Java中 [英] How to return 5 random "Powerball" numbers in Java

问题描述

尝试在Java中返回1到42之间的5个随机数。

我现在有逻辑返回一个单一的数字（把它放入一个ArrayList，但我想取消这个）。我很难实现返回5个随机数字。我需要5个循环吗？ （int i = 0; i <10; i ++）{
int r =（int）（b）
$ b

  Math.random（）* 42 + 1）; 
 
 $ / code> 

我在这里看到了一些其他相关的例子，它们看起来比我的需求决定。但是，我可能是错的。你可以使用 Set 来产生 > 5 唯一随机数字。



  Random random = new Random ）; 
 Set randomNumbers = new HashSet< Integer>（）; （randomNumbers.size（）<5）{
 randomNumbers.add（random.nextInt（42）+1）; 
。 
 
 
 
 
 
 $ b 
既然你提到过你正在使用 ArrayList ，它将包含所有的随机数字，你可以将 randomNumbers 中的所有元素添加到你的 ArrayList 。
 
 
 
 更新：  
 
 
你的需要，你需要做这样的事情： -  $ / b> 
 
 
  Random random = new Random（）; 
 Set< String> set = new HashSet< String>（）; （set.ize（）<5）{
 set.add（String.valueOf（random.nextInt（42）+1））; 
} 
 fortuneList3.addAll（set）; 
  
 
Trying to return 5 random numbers between 1 and 42 in Java.  

I currently have logic to return a single number (putting it into an ArrayList, but I'd like to do away with that.)  I'm stumped on implementation to return 5 random numbers.  Would I need 5 for loops?  
    for (int i = 0; i < 10; i++) {
        int r = (int) (Math.random() * 42 + 1);
    }
I've seen some other related examples here and they seem more complex than what my needs dictate.  However, I could be wrong.  
解决方案
You can use the Set to generate 5 Unique Random numbers.
Random random = new Random();
Set randomNumbers = new HashSet<Integer>();
while(randomNumbers.size()< 5) {
    randomNumbers.add(random.nextInt(42)+1);
}
Since you've mentioned that you're using an ArrayList which will hold all the random numbers, you could just add all the elements present in randomNumbers set to your ArrayList.

Update:-

To suit your needs, you need to do something like this:-
Random random = new Random();
Set<String> set = new HashSet<String>();
while(set.size()< 5) {
    set.add(String.valueOf(random.nextInt(42)+1));
}
fortuneList3.addAll(set);


                        
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