了解iOS Swift 2中的随机数 [英] Understanding random numbers in iOS Swift 2

问题描述

我如何使程序中的随机数不断变化（IE会在我每次使用它的范围内变成新的随机数）？

How do I make a random number continue to change over time in the program (I.E. become a new one within the range everytime I want to use it)?

我很沮丧我已经阅读了20多篇有关如何使用这种语言生成随机数的文章和文章（我很陌生），但我似乎无法使其正常工作。

I'm stumped. I've read more than 20 different posts and articles on how to generate random numbers in this language (which I'm pretty new to) and I just can't seem to get it to work.

我基本上是在尝试从1.0-3.0随机获得一个两倍。我可以很容易地做到这一点，但是一旦选择了这个数字，它就不会改变。这是我使用的代码：

I'm basically trying to get a random double from 1.0-3.0. I can do this pretty easily, but once it has selected that number it doesn't change. This is my code that I use:

var randomNumber:Double = (Double(arc4random() % 3) + 1);

然后我将其用作该行的值：

Then I use this as a value for the line:

SKAction.waitForDuration(randomNumber)

每个每次运行此程序时，我都想再次更改数字，但是一旦程序启动，它将继续使用相同的数字（每次重置程序时，数字都会不同）

Every time I run this I want to change the number again, but once the program starts it continues that same number (It's different every time i reset the program)

我了解来生成数字，但是我似乎在更新它时找不到任何东西！

I understand how to generate the number, but I can't seem to find anything on updating it!

我尝试添加

randomNumber = (Double(arc4random() % 3) + 1);

在将要多次运行的位置插入代码，但仍然给我相同的感觉

into the code in a spot where it will be ran many times, but it still gives me the same thing.

我对c ++非常熟悉，因此，如果您试图解释某些内容，可以参考其样式，我很可能会理解。

I'm very familiar with c++ so if you're trying to explain something you can reference its style and I will most likely understand.

推荐答案

使用：

SKAction.waitForDuration(sec: NSTimeInterval, withRange: NSTimeInterval) 

其中sec是您想要的时间范围的中间

where sec is the middle of the range in time you want to use, since range goes in a +- direction.

因此，在您的情况下，您需要：

So in your case you want:

SKAction.waitForDuration(2, withRange: 2),  this will get you a range of 1 to 3 (-1 to 1 range)

如果由于某种原因您需要一种会不断创建新的随机等待的方法，则可以始终这样做：

If for some reason you need a method that will constantly create a new random wait, you can always do:

extension SKAction
{
    func waitForRandomDuration() -> SKAction
    {
        var randomNumber:Double = (Double(arc4random() % 3) + 1);
        return SKAction.waitForDuration(randomNumber);

    }
}

然后确保添加每次需要完成此操作时，这都是对精灵的一种新操作，如果将其存储到变量中，则随机性不会改变。

And then make sure that you add this as a new action onto your sprite every time you need to get it done, if you store it into a variable, your randomness won't change.

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