Validate a email from a string

- (BOOL)isValidEmailWithString:(NSString*)string
{
    if ([string length] > 0) {
        BOOL stricterFilter = NO;
        NSString *stricterFilterString = @"[A-Z0-9a-z\\._%+-]+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}";
        NSString *laxString = @".+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2}[A-Za-z]*";
        NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;
        NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
        return [emailTest evaluateWithObject:string];
    }

    return NO;
}