在 Swift 中生成一个范围内的随机整数的最简单方法是什么? [英] What is the easiest way to generate random integers within a range in Swift?

问题描述

到目前为止我设计的方法是这样的:

The method I've devised so far is this:

func randRange (lower : Int , upper : Int) -> Int {
    let difference = upper - lower
    return Int(Float(rand())/Float(RAND_MAX) * Float(difference + 1)) + lower
}

这会生成上下限之间的随机整数.

This generates random integers between lower and upper inclusive.

推荐答案

这里有一个更简单的版本:

Here's a somewhat lighter version of it:

func randRange (lower: Int , upper: Int) -> Int {
    return lower + Int(arc4random_uniform(UInt32(upper - lower + 1)))
}

如果您决定此函数仅适用于无符号值，则可以进一步简化:

This can be simplified even further if you decide this function works with unsigned values only:

func randRange (lower: UInt32 , upper: UInt32) -> UInt32 {
    return lower + arc4random_uniform(upper - lower + 1)
}

或者，按照 Anton(为您 +1)使用范围作为参数的绝妙想法:

Or, following Anton's (+1 for you) excellent idea of using a range as parameter:

func random(range: Range<UInt32>) -> UInt32 {
    return range.startIndex + arc4random_uniform(range.endIndex - range.startIndex + 1)
}

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