将400电话当中加上-线

- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.        NSLog(@"--iphone--%@",[self getNewPhoneStr1:@"18502368888"]);    }//只需传一个电话进去，可以返回一个处理好的加了-线的400电话字符串，如传4001234567，返回400-123-4567- (NSString *)getNewPhoneStr1:(NSString *)phonestr{    if ([phonestr rangeOfString:@"-"].length == 0 && phonestr.length > 6) {        NSMutableString *phoneNumber = [NSMutableString string];        NSString *subStr = [phonestr substringToIndex:3];        [phoneNumber appendFormat:@"%@-",subStr];        subStr = [phonestr substringWithRange:NSMakeRange(3, 3)];        [phoneNumber appendFormat:@"%@-",subStr];        subStr = [phonestr substringWithRange:NSMakeRange(6, phonestr.length-6)];        [phoneNumber appendString:subStr];                phonestr = phoneNumber;    }        return phonestr;}