我该如何在Swift中生成随机的字母数字字符串?
Swift 4.2 更新
在处理随机值和元素方面,Swift 4.2引入了重大改进。您可以在此处阅读有关这些改进的更多信息。下面是该方法简化后的几行代码:
func randomString(length: Int) -> String {
let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
return String((0..<length).map{ _ in letters.randomElement()! })
}
Swift 3.0更新
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
}
抱歉,我只能使用英语作为我的输入和输出语言。func randomStringWithLength (len : Int) -> NSString {
let letters : NSString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var randomString : NSMutableString = NSMutableString(capacity: len)
for (var i=0; i < len; i++){
var length = UInt32 (letters.length)
var rand = arc4random_uniform(length)
randomString.appendFormat("%C", letters.characterAtIndex(Int(rand)))
}
return randomString
}
这是一个使用更加简洁的Swift语法的现成解决方案。您只需复制并粘贴即可:
func randomAlphaNumericString(length: Int) -> String {
let allowedChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
let allowedCharsCount = UInt32(allowedChars.characters.count)
var randomString = ""
for _ in 0 ..< length {
let randomNum = Int(arc4random_uniform(allowedCharsCount))
let randomIndex = allowedChars.index(allowedChars.startIndex, offsetBy: randomNum)
let newCharacter = allowedChars[randomIndex]
randomString += String(newCharacter)
}
return randomString
}
如果您更喜欢一个还具有一些方便功能的框架,请随时查看我的项目HandySwift。它还包括一个美丽的随机字母数字字符串解决方案:
String(randomWithLength: 8, allowedCharactersType: .alphaNumeric) // => "2TgM5sUG"
您也可以按照以下方式使用:
extension String {
static func random(length: Int = 20) -> String {
let base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var randomString: String = ""
for _ in 0..<length {
let randomValue = arc4random_uniform(UInt32(base.characters.count))
randomString += "\(base[base.startIndex.advancedBy(Int(randomValue))])"
}
return randomString
}
}
简单用法:
let randomString = String.random()
Swift 3 语法:
extension String {
static func random(length: Int = 20) -> String {
let base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var randomString: String = ""
for _ in 0..<length {
let randomValue = arc4random_uniform(UInt32(base.characters.count))
randomString += "\(base[base.index(base.startIndex, offsetBy: Int(randomValue))])"
}
return randomString
}
}
Swift 4 语法:
extension String {
static func random(length: Int = 20) -> String {
let base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var randomString: String = ""
for _ in 0..<length {
let randomValue = arc4random_uniform(UInt32(base.count))
randomString += "\(base[base.index(base.startIndex, offsetBy: Int(randomValue))])"
}
return randomString
}
}
Swift:
let randomString = NSUUID().uuidString
简单快速 -- UUID().uuidString
// 返回由 UUID 创建的字符串,例如“E621E1F8-C36C-495A-93FC-0C247A3E6E5F”。
public var uuidString: String { get }
Swift 3.0
let randomString = UUID().uuidString //0548CD07-7E2B-412B-AD69-5B2364644433
print(randomString.replacingOccurrences(of: "-", with: ""))
//0548CD077E2B412BAD695B2364644433
编辑
请不要将其与UIDevice.current.identifierForVendor?.uuidString
混淆,它不会提供随机值。
这里有一个非常清晰的函数,可以进行缓存。作为良好实践的一部分,您应该确保进行缓存。(当然,在应用程序中,缓存还具有微小的性能优势,但这完全无关紧要。)
func randomNameString(length: Int = 7)->String{
enum s {
static let c = Array("abcdefghjklmnpqrstuvwxyz12345789")
static let k = UInt32(c.count)
}
var result = [Character](repeating: "-", count: length)
for i in 0..<length {
let r = Int(arc4random_uniform(s.k))
result[i] = s.c[r]
}
return String(result)
}
这是用于当您有一个固定、已知的字符集时。
方便提示:
没有 0、o、O、i 等... 这些是人们经常混淆的字符。
通常在预订代码和类似代码中使用此方法,人类客户会使用这些代码。
repeating:count:
点赞。 - CœurSwift 5.0
// Generating Random String
func randomString(length: Int) -> String {
let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
return String((0..<length).map{ _ in letters.randomElement()! })
}
// Calling to string
label.text = randomString(length: 3)
使用 Swift 4.2,您最好的选择是创建一个包含所需字符的字符串,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)
我在这里详细阐述了这些更改。
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)
}
这种方法虽然长度限制为43个字符,但是它可以避免循环。如果需要更多字符,可以进行修改。与仅使用UUID相比,这种方法有两个优点:
UUID()
仅生成大写字母UUID
最长只能达到36个字符(包括4个连字符),但不带连字符时只有32个字符。如果需要更长的字符串或不想包含连字符,则使用base64EncodedString
即可处理此外,这个函数利用了一个UInt
来避免负数。
func generateRandom(size: UInt) -> String {
let prefixSize = Int(min(size, 43))
let uuidString = UUID().uuidString.replacingOccurrences(of: "-", with: "")
return String(Data(uuidString.utf8)
.base64EncodedString()
.replacingOccurrences(of: "=", with: "")
.prefix(prefixSize))
}
在循环中调用它以检查输出:
for _ in 0...10 {
print(generateRandom(size: 32))
}
将产生:
Nzk3NjgzMTdBQ0FBNDFCNzk2MDRENzZF
MUI5RURDQzE1RTdCNDA3RDg2MTI4QkQx
M0I3MjJBRjVFRTYyNDFCNkI5OUM1RUVC
RDA1RDZGQ0IzQjI1NDdGREI3NDgxM0Mx
NjcyNUQyOThCNzhCNEVFQTk1RTQ3NTIy
MDkwRTQ0RjFENUFGNEFDOTgyQTUxODI0
RDU2OTNBOUJGMDE4NDhEODlCNEQ1NjZG
RjM2MTUxRjM4RkY3NDU2OUFDOTI0Nzkz
QzUwOTE1N0U1RDVENDE4OEE5NTM2Rjcy
Nzk4QkMxNUJEMjYwNDJDQjhBQkY5QkY5
ODhFNjU0MDVEMUI2NEI5QUIyNjNCNkVF