NSMutableDictionary 與 NSMutableArray注意的地方

//NSMutableDictionary 與 NSMutableArray注意的地方
-(void)testDic
{
    //初始化
    NSMutableDictionary *dic = [[NSMutableDictionary alloc]init];
    NSMutableDictionary *dic1 = [[NSMutableDictionary alloc]init];
    NSMutableArray *arr = [[NSMutableArray alloc]init];
    //在里面添加數據
    [dic setObject:@"qingjoin" forKey:@"Name"];
    [dic setObject:@"100" forKey:@"Id"];
    
    [dic1 setObject:@"cook" forKey:@"Name"];
    [dic1 setObject:@"99" forKey:@"Id"];
    //再把兩個 NSMutableDictionary 里的數據添加到 NSMutableArray
    [arr addObject:dic];
    [arr addObject:dic1];
    //這時NSMutableArray里就有了兩組數據。
    //初始化
    //NSMutableDictionary *saveDic = [[NSMutableDictionary alloc]init];
    /*外面初始化會導致saveDic的值只可能有一組*/
    NSMutableArray *saveArr = [[NSMutableArray alloc]init];
    int count = [arr count]; //為2
    for(int i = 0; i<count; i++)
    {
        if([[[arr objectAtIndex:i]objectForKey:@"Name"]length]>0)
        {   
            /*這個地方要注意。saveDic的初始化只能在這里面。如果是在外面那么saveArr的值就只能是一后面得到的saveDic的值只有一組*/
            NSMutableDictionary *saveDic = [[NSMutableDictionary alloc]init]; 
            //把從arr里的兩組數據分別給saveDic 
            [saveDic setObject:[[arr objectAtIndex:i]objectForKey:@"Name"]forKey:@"Name"];
            [saveDic setObject:[[arr objectAtIndex:i]objectForKey:@"Id"] forKey:@"Id"];
            [saveArr addObject:saveDic];
        }
    }
    
    NSLog(@"saveArr:%@",[[saveArr objectAtIndex:0]objectForKey:@"Name"]); //name 打印出來為qingjoin 
    NSLog(@"saveArr:%@",[[saveArr objectAtIndex:1]objectForKey:@"Name"]); //name 打印出來為cook
    //如果saveDic 初始化放在外面 。那么name 打印出來為都為cook
}