如何验证一个电子邮件地址在swift?

有人知道如何在Swift中验证电子邮件地址吗?我找到了这个代码:

- (BOOL) validEmail:(NSString*) emailString {

    if([emailString length]==0){
        return NO;
    }

    NSString *regExPattern = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";

    NSRegularExpression *regEx = [[NSRegularExpression alloc] initWithPattern:regExPattern options:NSRegularExpressionCaseInsensitive error:nil];
    NSUInteger regExMatches = [regEx numberOfMatchesInString:emailString options:0 range:NSMakeRange(0, [emailString length])];

    NSLog(@"%i", regExMatches);
    if (regExMatches == 0) {
        return NO;
    } else {
        return YES;
    }
}

但我无法翻译成斯威夫特。

当前回答

这是@Fattie的“THE REASONABLE SOLUTION”的新版本，在Swift 4.1的一个名为String+Email.swift的新文件中测试:

import Foundation

extension String {
    private static let __firstpart = "[A-Z0-9a-z]([A-Z0-9a-z._%+-]{0,30}[A-Z0-9a-z])?"
    private static let __serverpart = "([A-Z0-9a-z]([A-Z0-9a-z-]{0,30}[A-Z0-9a-z])?\\.){1,5}"
    private static let __emailRegex = __firstpart + "@" + __serverpart + "[A-Za-z]{2,6}"

    public var isEmail: Bool {
        let predicate = NSPredicate(format: "SELF MATCHES %@", type(of:self).__emailRegex)
        return predicate.evaluate(with: self)
    }
}

所以它的用法很简单:

let str = "mail@domain.com"
if str.isEmail {
    print("\(str) is a valid e-mail address")
} else {
    print("\(str) is not a valid e-mail address")
}

我只是不喜欢向String对象添加func，因为作为电子邮件地址是它们固有的(或不是)。根据我的理解，Bool属性比func更适合。

2018-05-15 17:52:07

其他回答

更新答案@Arsonik对Swift 2.2的回答，使用比其他提供的解决方案更少的冗长代码:

extension String {
    func isValidEmail() -> Bool {
        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: [], range: NSMakeRange(0, self.characters.count)) != nil
    }
}

2016-08-09 21:26:31

完美的正则表达式，如谷歌电子邮件

"^[A-Z0-9a-z][a-zA-Z0-9_.-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"

2017-09-22 07:58:04

我更喜欢用扩展名。此外，这个url http://emailregex.com可以帮助您测试regex是否正确。事实上，该站点为某些编程语言提供了不同的实现。我分享了Swift 3的实现。

extension String {
    func validateEmail() -> Bool {
        let emailRegex = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,6}"
        return NSPredicate(format: "SELF MATCHES %@", emailRegex).evaluate(with: self)
    }
}

2016-10-26 15:53:21

或者你可以扩展可选文本UITextField:

使用方法:

if  emailTextField.text.isEmailValid() {
      print("email is valid")
}else{
      print("wrong email address")
}

扩展:

extension Optional where Wrapped == String {
    func isEmailValid() -> Bool{
        guard let email = self else { return false }
        let emailPattern = "[A-Za-z-0-9.-_]+@[A-Za-z0-9]+\\.[A-Za-z]{2,3}"
        do{
            let regex = try NSRegularExpression(pattern: emailPattern, options: .caseInsensitive)
            let foundPatters = regex.numberOfMatches(in: email, options: .anchored, range: NSRange(location: 0, length: email.count))
            if foundPatters > 0 {
                return true
            }
        }catch{
            //error
        }
        return false
    }
}

2017-11-23 11:21:44

我会使用npredicate:

func isValidEmail(_ email: String) -> Bool {        
    let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"

    let emailPred = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
    return emailPred.evaluate(with: email)
}

对于Swift 3.0之前的版本:

func isValidEmail(email: String) -> Bool {
    let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"

    let emailPred = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
    return emailPred.evaluate(with: email)
}

对于Swift 1.2之前的版本:

func isValidEmail(email: String) -> Bool {
    let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"

    if let emailPred = NSPredicate(format:"SELF MATCHES %@", emailRegEx) {
        return emailPred.evaluateWithObject(email)
    }
    return false
}

2014-08-24 11:20:20

如何验证一个电子邮件地址在swift?

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