如何在不重复Swift的情况下生成随机数

-2

我对Swift和一般编程非常陌生，所以请耐心等待，而我试图弄清楚这一点。如何在不重复Swift的情况下生成随机数

我一直在从树屋跟随Swift的初学者课程，并设法开发一个简单的应用程序，生成随机引号。到现在为止还挺好。现在，在开始学习更高级的课程之前，我想先试着更新现有的应用程序，以确保在继续前进行一些扎实的练习。

所以这里是我的问题：我设法通过GameKit框架生成一个随机数，但问题是有时引号会连续出现。我怎样才能避免这种情况发生？

这里是我的代码：

import GameKit 

struct FactProvider { 
    let facts = [ 
     "Ants stretch when they wake up in the morning.", 
     "Ostriches can run faster than horses.", 
     "Olympic gold medals are actually made mostly of silver.", 
     "You are born with 300 bones; by the time you are an adult you will have 206.", 
     "It takes about 8 minutes for light from the Sun to reach Earth.", 
     "Some bamboo plants can grow almost a meter in just one day.", 
     "The state of Florida is bigger than England.", 
     "Some penguins can leap 2-3 meters out of the water.", 
     "On average, it takes 66 days to form a new habit.", 
     "Mammoths still walked the Earth when the Great Pyramid was being built." 
    ] 

    func randomFact() -> String { 
     let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: facts.count) 
     return facts[randomNumber] 
    } 
}

来源

2017-05-09 imalexdae

您的设置只有10个元素宽。所以你应该期望一些重复最终发生 – Machavity

请看看“相关”的问题，如http://stackoverflow.com/questions/27541145/how-to-generate-a-random-number-in-swift -with-repeated-the-before-random-n和http://stackoverflow.com/questions/26457632/how-to-generate-random-numbers-without-repetition-in-swift。 - 当然http://stackoverflow.com/questions/24026510/how-do-i-shuffle-an-array-in-swift –

@Machavity是无关紧要的。我需要他们洗牌，而不是连续两次显示相同的报价。 – imalexdae

可以最后随机数或最后的事实存储在一个变量，并检查它在你的randomFact功能。像这样：

var lastRandomNumber = -1 

func randomFact() -> String { 
    let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: facts.count) 

    if randomNumber == lastRandomNumber { 
     return randomFact() 
    } else { 
     lastRandomNumber = randomNumber 
     return facts[randomNumber] 
    } 
}

来源

2017-05-09 14:46:07 dilaver

谢谢你的帮助Dilaver。我很感激。 – imalexdae

-1

使用arc4Random：

let max = 5 
    let f = Int(arc4random_uniform(UInt32(max))) 
    let i = Int(Float(f)) + 1; // generates # between 1 and max - 1

来源

2017-05-09 13:33:33

如何在不重复Swift的情况下生成随机数

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