Java: public static boolean isValidEmail(CharSequence target) { return (!TextUtils.isEmpty(target) && Patterns.EMAIL_ADDRESS.matcher(target).matches()); } Kotlin: fun CharSequence?.isValidEmail() = !isNullOrEmpty() && Patterns.EMAIL_ADDRESS.matcher(this).matches() Edit: It will work On Android 2.2+ onwards !! Edit: Added missing ;
If you are using .NET Framework 4.5, the solution is to use EmailAddressAttribute which resides inside System.ComponentModel.DataAnnotations. Your code should look similar to this: [Display(Name = “Email address”)] [Required(ErrorMessage = “The email address is required”)] [EmailAddress(ErrorMessage = “Invalid Email Address”)] public string Email { get; set; }
The answer to Using a regular expression to validate an email address explains in great detail that the grammar specified in RFC 5322 is too complicated for primitive regular expressions. I recommend a real parser approach like MKEmailAddress. As quick regular expressions solution see this modification of DHValidation: – (BOOL) validateEmail: (NSString *) candidate { … Read more
To match pattern or an empty string, use ^$|pattern Explanation ^ and $ are the beginning and end of the string anchors respectively. | is used to denote alternates, e.g. this|that. References regular-expressions.info/Anchors and Alternation On \b \b in most flavor is a “word boundary” anchor. It is a zero-width match, i.e. an empty string, … Read more
You can theoretically have an address without a “.” in. Since technically things such as: user@com user@localserver user@[IPv6:2001:db8::1] Are all valid emails. So the standard HTML5 validation allows for all valid E-mails, including the uncommon ones. For some easy to read explanations (Instead of reading through the standards): http://en.wikipedia.org/wiki/Email_address#Examples Update from a comment: ICANN banned … Read more
Have you looked at PHP’s filter_ functions? They’re not perfect, but they do a fairly decent job in my experience. Example usage (returns boolean): filter_var($someEmail, FILTER_VALIDATE_EMAIL);
The easiest and safest way to check whether an email address is well-formed is to use the filter_var() function: if (!filter_var($email, FILTER_VALIDATE_EMAIL)) { // invalid emailaddress } Additionally you can check whether the domain defines an MX record: if (!checkdnsrr($domain, ‘MX’)) { // domain is not valid } But this still doesn’t guarantee that the … Read more
Using regular expressions is probably the best way. You can see a bunch of tests here (taken from chromium) const validateEmail = (email) => { return String(email) .toLowerCase() .match( /^(([^<>()[\]\\.,;:\s@”]+(\.[^<>()[\]\\.,;:\s@”]+)*)|(“.+”))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/ ); }; Here’s the example of a regular expression that accepts unicode: const re = /^(([^<>()[\]\.,;:\s@\”]+(\.[^<>()[\]\.,;:\s@\”]+)*)|(\”.+\”))@(([^<>()[\]\.,;:\s@\”]+\.)+[^<>()[\]\.,;:\s@\”]{2,})$/i; But keep in mind that one should not rely … Read more
UPDATES http://so.lucafilosofi.com/jquery-validate-e-mail-address-regex/ using new regex added support for Address tags (+ sign) function isValidEmailAddress(emailAddress) { var pattern = /^([a-z\d!#$%&’*+\-\/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+(\.[a-z\d!#$%&’*+\-\/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+)*|”((([ \t]*\r\n)?[ \t]+)?([\x01-\x08\x0b\x0c\x0e-\x1f\x7f\x21\x23-\x5b\x5d-\x7e\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|\\[\x01-\x09\x0b\x0c\x0d-\x7f\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))*(([ \t]*\r\n)?[ \t]+)?”)@(([a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|[a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF][a-z\d\-._~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]*[a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])\.)+([a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|[a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF][a-z\d\-._~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]*[a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])\.?$/i; return pattern.test(emailAddress); } if( !isValidEmailAddress( emailaddress ) ) { /* do stuff here */ } NOTE: keep in mind that no 100% regex email check exists!
What about this? bool IsValidEmail(string email) { var trimmedEmail = email.Trim(); if (trimmedEmail.EndsWith(“.”)) { return false; // suggested by @TK-421 } try { var addr = new System.Net.Mail.MailAddress(email); return addr.Address == trimmedEmail; } catch { return false; } } Per Stuart’s comment, this compares the final address with the original string instead of always returning … Read more