是否以字母开头

• (BOOL)fromLettersStart:(NSString *)string {
  if(string.length < 1) {
  return NO;
  }
  NSString *firstStr = [string substringToIndex:1];
  NSString regex = @"[a-zA-Z]";
  NSPredicate *pre = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];
  return [pre evaluateWithObject: firstStr];
  }

是否以汉字开头

• (BOOL)fromChineseStart:(NSString *)string {
  if(string.length < 1) {
  return NO;
  }
  NSString *firstStr = [string substringToIndex:1];
  NSString *regex = @"[\u4e00-\u9fa5]+";
  NSPredicate *pre = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];
  return [pre evaluateWithObject: firstStr];
  }

是否是手机号

• (BOOL)isMobilePhone:(NSString )string {
  if(string.length != 11) {
  return NO;
  }
  /*
  * 移动号段: 134,135,136,137,138,139,150,151,152,157,158,159,182,183,184,187,188,147,178,1705
  * 联通号段: 130,131,132,155,156,185,186,145,176,1709
  * 电信号段: 133,153,180,181,189,177,1700
  */
  NSString *MOBILE = @"^1(3[0-9]|4[57]|5[0-35-9]|8[0-9]|7[0678])\d{8}$";
  NSPredicate *pre = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", MOBILE];
  return [pre evaluateWithObject: string];
  }

银行卡号有效性

+ (BOOL)isBankCardNumber:(NSString *)string {
    if(string.length < 10) {
        return NO;   
    }
    NSString * lastNum = [[string substringFromIndex:(string.length-1)] copy];
    NSString * forwardNum = [[string substringToIndex:(string.length -1)] copy];
    NSMutableArray * forwardArr = [[NSMutableArray alloc] initWithCapacity:0];
    for (int i=0; i<forwardNum.length; i++) {
        NSString * subStr = [forwardNum substringWithRange:NSMakeRange(i, 1)];
        [forwardArr addObject:subStr];
    }
    NSMutableArray * forwardDescArr = [[NSMutableArray alloc] initWithCapacity:0];
    for (int i = (int)(forwardArr.count-1); i> -1; i--) {
        [forwardDescArr addObject:forwardArr[i]];
    }
    NSMutableArray * arrOddNum = [[NSMutableArray alloc] initWithCapacity:0];
    NSMutableArray * arrOddNum2 = [[NSMutableArray alloc] initWithCapacity:0];
    NSMutableArray * arrEvenNum = [[NSMutableArray alloc] initWithCapacity:0];
    for (int i=0; i< forwardDescArr.count; i++) {
        NSInteger num = [forwardDescArr[i] intValue];
        if (i%2) {
            [arrEvenNum addObject:[NSNumber numberWithInteger:num]];
        }else{
            if (num * 2 < 9) {
                [arrOddNum addObject:[NSNumber numberWithInteger:num * 2]];
            }else{
                NSInteger decadeNum = (num * 2) / 10;
                NSInteger unitNum = (num * 2) % 10;
                [arrOddNum2 addObject:[NSNumber numberWithInteger:unitNum]];
                [arrOddNum2 addObject:[NSNumber numberWithInteger:decadeNum]];
            }
        }
    }
    __block  NSInteger sumOddNumTotal = 0;
    [arrOddNum enumerateObjectsUsingBlock:^(NSNumber * obj, NSUInteger idx, BOOL *stop) {
        sumOddNumTotal += [obj integerValue];
    }];
    __block NSInteger sumOddNum2Total = 0;
    [arrOddNum2 enumerateObjectsUsingBlock:^(NSNumber * obj, NSUInteger idx, BOOL *stop) {
        sumOddNum2Total += [obj integerValue];
    }];
    __block NSInteger sumEvenNumTotal =0 ;
    [arrEvenNum enumerateObjectsUsingBlock:^(NSNumber * obj, NSUInteger idx, BOOL *stop) {
        sumEvenNumTotal += [obj integerValue];
    }];
    NSInteger lastNumber = [lastNum integerValue];
    NSInteger luhmTotal = lastNumber + sumEvenNumTotal + sumOddNum2Total + sumOddNumTotal;
    return (luhmTotal%10 ==0)?YES:NO;
}