Question

我有以下示例代码：

NSNumber * number1 = @231;
NSNumber * number2 = @322;
NSLog(@"number1: %@", number1);
NSLog(@"number2: %@", number2);
NSMutableDictionary* dict = [NSMutableDictionary new];
[dict setObject:number1 forKey:@"number"];
NSNumber * outNumber = [dict objectForKey:@"number"];
NSLog(@"outNumber: %@",outNumber);
[dict setObject:number2 forKey:@"number"];
NSLog(@"outNumber: %@",outNumber);

更新字典中“number”键下的值后，outNumber对象仍然指向上一个值（231）。

在Objective-C中是否有一种方法可以使outNumber对象始终指向字典中“number”键下的当前值？

Answer 1

您没有打印更新的字典，所以在代码末尾添加以下2行：

NSNumber * outNumber2 = [dict objectForKey:@"number"];
NSLog(@"outNumber: %@",outNumber2);

希望对你有所帮助!!

指向NSMutableDictionary对象的指针

1 个答案: