Regex for an email address doesn't work

Question

I\'m trying to check if some email address is correct with the following code :

NSPredicate *regexMail = [NSPredicate predicateWithFormat:@\"SELF MATCHES \'.*@.*         


        

Answer 1

This page has a good explanation of using regular expressions to validate email, as well as some regexes:

http://www.regular-expressions.info/email.html

Their expression:

[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?

Seems to be the best tradeoff between thoroughness and correctness.

Answer 2

This is the regular expression used by the iOS Mail application to validate an email address:

^[[:alnum:]!#$%&’*+/=?^_`{|}~-]+((\.?)[[:alnum:]!#$%&’*+/=?^_`{|}~-]+)*@[[:alnum:]-]+(\.[[:alnum:]-]+)*(\.[[:alpha:]]+)+$

And here is a copy/paste ready function using this regular expression to validate an email address in Objective-C:

BOOL IsValidEmail(NSString *email)
{
    // Regexp from -[NSString(NSEmailAddressString) mf_isLegalEmailAddress] in /System/Library/PrivateFrameworks/MIME.framework
    NSString *emailRegex = @"^[[:alnum:]!#$%&'*+/=?^_`{|}~-]+((\\.?)[[:alnum:]!#$%&'*+/=?^_`{|}~-]+)*@[[:alnum:]-]+(\\.[[:alnum:]-]+)*(\\.[[:alpha:]]+)+$";
    NSPredicate *emailPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
    return [emailPredicate evaluateWithObject:email];
}