在Swift 5.7中，在Regex类的帮助下，我们可以以简单有效的方式验证电子邮件地址

private func isValidEmail(_ email: String) -> Bool {
      guard let emailRegex = try? Regex("[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}")  
      else { return false }
      return email.firstMatch(of: emailRegex) != nil
   }

我们还可以使用属性包装器来提高效率:

@propertyWrapper
struct EmailPropertyWrapper {
  private var _value: String
  var wrappedValue: String {
    get { return isValidEmail(_value) ? _value : String() }
    set { _value = newValue }
  }
  
  init(email: String) {
    _value = email
  }

  private func isValidEmail(_ email: String) -> Bool {
      guard let emailRegex = try? Regex("[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}")  
      else { return false }
      return email.firstMatch(of: emailRegex) != nil
   }
}

struct User {
  var name: String
  @EmailPropertyWrapper var email: String
  
  func validateProperty() -> Bool {
    if name.isEmpty || email.isEmpty { return false }
    return true
  }
}

let user = User(name: "Sy", email: .init(email: "wwdc@icloud.com"))

print(user.validateProperty())

@JeffersonBe的答案是接近的，但如果字符串是“包含someone@something.com一个有效的电子邮件”，这不是我们想要的。下面是String上的一个扩展，它工作得很好(并且允许测试有效的phoneNumber和其他数据检测器来引导。

/// Helper for various data detector matches.
/// Returns `true` iff the `String` matches the data detector type for the complete string.
func matchesDataDetector(type: NSTextCheckingResult.CheckingType, scheme: String? = nil) -> Bool {
    let dataDetector = try? NSDataDetector(types: type.rawValue)
    guard let firstMatch = dataDetector?.firstMatch(in: self, options: NSRegularExpression.MatchingOptions.reportCompletion, range: NSRange(location: 0, length: length)) else {
        return false
    }
    return firstMatch.range.location != NSNotFound
        // make sure the entire string is an email, not just contains an email
        && firstMatch.range.location == 0
        && firstMatch.range.length == length
        // make sure the link type matches if link scheme
        && (type != .link || scheme == nil || firstMatch.url?.scheme == scheme)
}
/// `true` iff the `String` is an email address in the proper form.
var isEmail: Bool {
    return matchesDataDetector(type: .link, scheme: "mailto")
}
/// `true` iff the `String` is a phone number in the proper form.
var isPhoneNumber: Bool {
    return matchesDataDetector(type: .phoneNumber)
}
/// number of characters in the `String` (required for above).
var length: Int {
    return self.characters.count
}

我为输入验证设计了一个库，其中一个“模块”可以让你轻松地验证一堆东西…

例如，要验证一封电子邮件:

let emailTrial = Trial.Email
let trial = emailTrial.trial()

if(trial(evidence: "test@test.com")) {
   //email is valid
}

SwiftCop是图书馆…希望能有所帮助!

下面是两个投票最多的答案与正确的正则表达式的融合:一个使用谓词的字符串扩展，因此您可以调用String . isemail

    extension String {
        var isEmail: Bool {
           let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,20}"            
           let emailTest  = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
           return emailTest.evaluateWithObject(self)
        }
    }

这是Swift 2.0 - 2.2的更新版本

 var isEmail: Bool {
    do {
        let regex = try NSRegularExpression(pattern: "^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$", options: .CaseInsensitive)
        return regex.firstMatchInString(self, options: NSMatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count)) != nil
    } catch {
        return false
    }
}

对于swift 2.1:这可以通过电子邮件foo@bar正常工作

extension String {
    func isValidEmail() -> Bool {
        do {
            let regex = try NSRegularExpression(pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,6}", options: .CaseInsensitive)
            return regex.firstMatchInString(self, options: NSMatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count)) != nil
        } catch {
                return false
        }
    }
}