- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    //替换回车符和空格

    NSString *oldStr=@"  1   2   4   ";

    NSLog(@"----oldStr---%@",oldStr);

    //去掉首尾空格

    NSString *newStr=[oldStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

    NSLog(@"---newStr---%@",newStr);

    //去掉中间的空格

    NSString *newNewStr=[newStr stringByReplacingOccurrencesOfString:@" " withString:@""];

    NSLog(@"---newNewStr--%@",newNewStr);

}

2015-10-23 13:16:50.310 字符串替换回车和换行[7678:198286] ----oldStr---  1   2   4

2015-10-23 13:16:50.311 字符串替换回车和换行[7678:198286] ---newStr---1   2   4

2015-10-23 13:16:50.311 字符串替换回车和换行[7678:198286] ---newNewStr--