Email Validation in iOS

Question

Email validation checking in iPhone programming can be done using RegexKitLite library (iOS2.0), NSPredicate (iOS 3.0 onwards) and NSRegularExpression (iOS 4.0). But can anybody state what is the advantage of one over the other and which is the best validating option of the three stated.

Answer 1

i am using NSPredicate always...and it is working fine

NSString *emailid = emailField.text;
NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest =[NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
BOOL myStringMatchesRegEx=[emailTest evaluateWithObject:emailid];

Answer 2

My answer is a refactored one from the excellent solution provided in this link..

///Returns YES (true) if EMail is valid
+(BOOL) IsValidEmail:(NSString *)emailString Strict:(BOOL)strictFilter
{
    NSString *stricterFilterString = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSString *laxString = @".+@.+\\.[A-Za-z]{2}[A-Za-z]*";

    NSString *emailRegex = strictFilter ? stricterFilterString : laxString;
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

    return [emailTest evaluateWithObject:emailString];
}