objective-c中ARC的问题：初始化的时候无法读取值

Question

先看一下ARC：

NSMutableDictionary *datesDict = [[NSMutableDictionary alloc]init];
NSMutableArray *datesArray = [[NSMutableArray alloc]init];

for (NSString *key in programsArray) {

    datesArray = [_onDemandDictionary objectForKey:key];
    NSMutableArray *newDates = [[NSMutableArray alloc]init];
    int count;
    for (count = 0; count <datesArray.count; count++) {
        NSMutableDictionary *programsDict = [[NSMutableDictionary alloc]init];
        programsDict = [datesArray objectAtIndex:count];
        [newDates addObject:[programsDict objectForKey:@"date"]];

    }

    [datesDict setObject:newDates forKey:key];
}

在运行解析工具的时候，出现这一句：**stored to (datesArray and programsDict) during its initialization is never read**
在这一句

NSMutableArray *datesArray = [[NSMutableArray alloc]init];
programsDict = [datesArray objectAtIndex:count];

为什么？找不到原因和解决方法，请高人指点，谢谢！

Answer 1

问题出在你创建新的NSMutableArray.然后在这一句

NSMutableArray *datesArray = [[NSMutableArray alloc]init];

把它分配给datesArray，

但是接下来又把一个完全不同的值又分配给了datesArray

datesArray = [_onDemandDictionary objectForKey:key];

所以你最开始只要用这句就可以：

NSMutableArray *datesArray = nil;

和programsDict是一样的