我如何在Swift中生成一个随机的字母数字字符串?
当前回答
在Swift 4.2中,你最好的方法是创建一个包含你想要的字符的字符串,然后使用randomElement来选择每个字符:
let length = 32
let characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
let randomCharacters = (0..<length).map{_ in characters.randomElement()!}
let randomString = String(randomCharacters)
我将在这里详细介绍这些变化。
其他回答
一种避免输入整套字符的方法:
func randomAlphanumericString(length: Int) -> String {
enum Statics {
static let scalars = [UnicodeScalar("a").value...UnicodeScalar("z").value,
UnicodeScalar("A").value...UnicodeScalar("Z").value,
UnicodeScalar("0").value...UnicodeScalar("9").value].joined()
static let characters = scalars.map { Character(UnicodeScalar($0)!) }
}
let result = (0..<length).map { _ in Statics.characters.randomElement()! }
return String(result)
}
这是我能想到的最快的解决办法。斯威夫特3.0
extension String {
static func random(length: Int) -> String {
let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
let randomLength = UInt32(letters.characters.count)
let randomString: String = (0 ..< length).reduce(String()) { accum, _ in
let randomOffset = arc4random_uniform(randomLength)
let randomIndex = letters.index(letters.startIndex, offsetBy: Int(randomOffset))
return accum.appending(String(letters[randomIndex]))
}
return randomString
}
}
简单快捷——UUID().uuidString
//返回由UUID创建的字符串,例如"E621E1F8-C36C-495A-93FC-0C247A3E6E5F" uuidString:字符串{get} https://developer.apple.com/documentation/foundation/uuid
斯威夫特3.0
let randomString = UUID().uuidString //0548CD07-7E2B-412B-AD69-5B2364644433
print(randomString.replacingOccurrences(of: "-", with: ""))
//0548CD077E2B412BAD695B2364644433
EDIT
请不要与UIDevice.current.identifierForVendor混淆。uuidString它不会给出随机值。
如果您只需要一个唯一标识符UUID()。uuidString可以满足您的需求。
斯威夫特4
苹果推荐使用RandomNumberGenerator获得更好的性能
用法:String.random (20) 结果:CifkNZ9wy9jBOT0KJtV4
extension String{
static func random(length:Int)->String{
let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var randomString = ""
while randomString.utf8.count < length{
let randomLetter = letters.randomElement()
randomString += randomLetter?.description ?? ""
}
return randomString
}
}