可变字符串 NSMutableString 以及 随机产生不重复10以下的随机数

NSMutableString *goodListString=[[NSMutableString alloc]init];//初始化可变字符串
    for (int i=0; i<m_goodsInfo.count; i++) {
        [goodListString insertString:m_goodsInfo[i] atIndex:[goodListString length]];
    }


randomGenerate=[[NSMutableArray alloc]init];
    do{
        int random=arc4random()%10;//10以下可能会重复
        NSString *randomString=[NSString stringWithFormat:@"%d",random];
        if (![randomGenerate containsObject:randomString]) //产生不重复的随机数存到数组中
{
            [randomGenerate addObject:randomString];
        }
       
    }while (randomGenerate.count!=4);