随机字母数字字符串Linux Swift 3
尝试使用
Swift 3在
Linux中生成随机字符串时遇到2个问题.
> arc4random_uniform仅在BSD上的Linux中不可用.所以我能够使用random()函数逃脱.这在我生成可变大小的随机数时起作用(参见下面的代码) func generateRandomNumber() -> Int { var place = 1 var finalNumber = 0; #if os(Linux) for _ in 0..<5 { place *= 10 let randomNumber = Int(random() % 10) + 1 finalNumber += randomNumber * place } #else for _ in 0..<5 { place *= 10 let randomNumber = Int(arc4random_uniform(10)) finalNumber += randomNumber * place } #endif return finalNumber } 那个工作. >当尝试生成随机字母数字字符串时,我仅限于使用Swift String而不是NSSTRING. Linux抛出此错误 原始的Linux前代码块: func randomString(_ length: Int) -> String { let letters : NSString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" let len = UInt32(letters.length) var randomString = "" for _ in 0 ..< length { let rand = arc4random_uniform(len) var nextChar = letters.character(at: Int(rand)) randomString += NSString(characters: &nextChar,length: 1) as String } return randomString } 以及使用上面代码时得到的实际错误 error: cannot convert value of type 'NSString' to type 'String' in coercion randomString += NSString(characters: &nextChar,length: 1) as String 修改为linux代码块. func randomString(_ length: Int) -> String { let letters : String = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" let len = letters.characters.count var randomString = "" #if os(Linux) for _ in 0..<length { let randomValue = (random() % len) + 1 randomString += "(letters[letters.index(letters.startIndex,offsetBy: Int(randomValue))])" } #else for _ in 0 ..< length { let rand = arc4random_uniform(UInt32(len)) randomString += "(letters[letters.index(letters.startIndex,offsetBy: Int(rand))])" } #endif return randomString } 但这次错误很奇怪,它只是说没有额外信息的非法指令.我以交互模式运行了docker容器,我看到我的服务器正在运行并在调用其他函数时打印出来等. 但事实上,当我在IBM的swift中运行它时,函数实际上是可行的 我也假设它也使用linux.我非常困惑和困惑任何帮助将不胜感激. (更新):我在一个linux env中使用单个swift文件而不是Vapor swift web框架运行相同的功能.它的工作原理.正如我在上面的编辑中所提到的,它每次都给我相同的随机字符串.一旦我的构建完成,我仍然需要测试整个项目.但除此之外,我需要知道random()函数是否实际上每次给我一些新东西而不是相同的废话. 解决方法
弄清楚了.
所以重复随机数/字符串的答案就是在调用random()函数之前添加这一行 srand(UInt32(time(nil))) 我假设那也是修正非法指令的原因.因为我不记得改变其他任何东西. 不用说这是我的最终结果 func generateRandomNumber() -> Int { var place = 1 var finalNumber = 0; #if os(Linux) srand(UInt32(time(nil))) for _ in 0..<5 { place *= 10 let randomNumber = Int(random() % 10) + 1 finalNumber += randomNumber * place } #else for _ in 0..<5 { place *= 10 let randomNumber = Int(arc4random_uniform(10)) finalNumber += randomNumber * place } #endif return finalNumber } func randomString(_ length: Int) -> String { let letters : String = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" let len = letters.characters.count var randomString = "" #if os(Linux) srand(UInt32(time(nil))) for _ in 0..<length { let randomValue = (random() % len) + 1 randomString += "(letters[letters.index(letters.startIndex,offsetBy: Int(randomValue))])" } #else for _ in 0 ..< length { let rand = arc4random_uniform(UInt32(len)) randomString += "(letters[letters.index(letters.startIndex,offsetBy: Int(rand))])" } #endif return randomString } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |