验证

+ (BOOL) validateEmail:(NSString *)email
{
    NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
    return [emailTest evaluateWithObject:email];
}


//手机号码验证
+ (BOOL) validateMobile:(NSString *)mobile
{
    //手机号以13， 15，18开头，八个 \d 数字字符
    NSString *phoneRegex = @"^((13[0-9])|(15[^4,\\D])|(18[0,0-9]))\\d{8}$";
    NSPredicate *phoneTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",phoneRegex];
    return [phoneTest evaluateWithObject:mobile];
}

分组

NSString* test = @"abc";
        NSString *regexString = @"a(?:\w)(\w)";
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regexString options:NSRegularExpressionCaseInsensitive error:nil];
        NSArray *matches = [regex matchesInString:test
                                          options:0
                                          range:NSMakeRange(0, [test length])];
        if(matches.count==0){
            //没有匹配上
        }
        for (NSTextCheckingResult *match in matches) {
            NSString* group1 = [test substringWithRange:[match rangeAtIndex:1]];
            NSLog(@"%@", group1);

        }