这是一个最新的游乐场兼容版本，使用标准库，所以你不需要维护一个正则表达式:

import Foundation

func isValid(email: String) -> Bool {
  do {
    let detector = try NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
    let range = NSRange(location: 0, length: email.count)
    let matches = detector.matches(in: email, options: .anchored, range: range)
    guard matches.count == 1 else { return false }
    return matches[0].url?.scheme == "mailto"
  } catch {
    return false
  }
}

extension String {
  var isValidEmail: Bool {
    isValid(email: self)
  }
}

let email = "test@mail.com"
isValid(email: email) // prints 'true'
email.isValidEmail // prints 'true'

//Email validation
func validateEmail(enterEmail:String) -> Bool{
    let emailFormat = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"
    let emailPredicate = NSPredicate(format:"SELF MATCHES %@",emailFormat)
    return emailPredicate.evaluate(with:enterEmail)
}

100%工作和测试

对@和做一个简单的测试。然后发一封确认邮件。

考虑一下:

世界上有一半的人使用非ascii字符。 正则表达式是缓慢和复杂的。顺便说一下，至少检查字符/字母/Unicode范围，而不是az。 因为RFC规则和相应的正则表达式太复杂，所以无法进行完全验证。

我用的是这个基本的检查:

// similar to https://softwareengineering.stackexchange.com/a/78372/22077
import Foundation

/**
 Checks that
 - length is 254 or less (see https://stackoverflow.com/a/574698/412916)
 - there is a @ which is not the first character
 - there is a . after the @
 - there are at least 4 characters after the @
*/
func isValidEmail(email: String) -> Bool {
    guard email.count <= 254 else { 
        return false 
    }
    let pos = email.lastIndex(of: "@") ?? email.endIndex
    return (pos != email.startIndex)
        && ((email.lastIndex(of: ".") ?? email.startIndex) > pos) 
        && (email[pos...].count > 4)
}

print(isValidEmail(email: "アシッシュ@ビジネス.コム")) // true

请注意,

它比regex和NSDataDetector快得多。 它正确地报告以下内容为有效:

Håkan.Söderström@malmö.se"
punnycode@XN--0ZWM56D.XN--HGBK6AJ7F53BBA"
试@例子.测试.مثال.آزمایشی"
foo.bar+something@blah.com"
m@foo.co.uk

它错误地将以下内容报告为无效——因为它们实际上是有效的，但可能是用户错误的产物:

a @ b
a@b

相关:

电子邮件地址验证应该走多远? 在线电子邮件检查:https://isemail.info/

我建议使用它作为String的扩展:

extension String {    
    public var isEmail: Bool {
        let dataDetector = try? NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)

        let firstMatch = dataDetector?.firstMatch(in: self, options: NSRegularExpression.MatchingOptions.reportCompletion, range: NSRange(location: 0, length: length))

        return (firstMatch?.range.location != NSNotFound && firstMatch?.url?.scheme == "mailto")
    }

    public var length: Int {
        return self.characters.count
    }
}

要使用它:

if "hodor@gameofthrones.com".isEmail { // true
    print("Hold the Door")
}

创建简单的扩展:

extension NSRegularExpression {

    convenience init(pattern: String) {
        try! self.init(pattern: pattern, options: [])
    }
}

extension String {

    var isValidEmail: Bool {
        return isMatching(expression: NSRegularExpression(pattern: "^[A-Z0-9a-z\\._%+-]+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}$"))
    }

    //MARK: - Private

    private func isMatching(expression: NSRegularExpression) -> Bool {
        return expression.numberOfMatches(in: self, range: NSRange(location: 0, length: characters.count)) > 0
    }
}

例子:

"b@bb.pl".isValidEmail //true
"b@bb".isValidEmail //false

你可以扩展以下扩展到任何你需要的:isValidPhoneNumber, isValidPassword等…

这里有很多正确答案，但许多“正则表达式”是不完整的，可能会发生像“name@domain”这样的电子邮件结果是有效的电子邮件，但它不是。这里是完整的解决方案:

extension String {

    var isEmailValid: Bool {
        do {
            let regex = try NSRegularExpression(pattern: "(?:[a-z0-9!#$%\\&'*+/=?\\^_`{|}~-]+(?:\\.[a-z0-9!#$%\\&'*+/=?\\^_`{|}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])", options: .CaseInsensitive)
            return regex.firstMatchInString(self, options: NSMatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count)) != nil
        } catch {
            return false
        }
    }
}