比较包含NSStrings的NSDictionaries [英] Compare NSDictionaries containing NSStrings

问题描述

我有两个 NSDictionaries 包含 NSStrings 。为了比较这两个字典，我使用 isEqualToDictionary：方法。有关 isEqualToDictionary：的说明

I have two NSDictionaries containing NSStrings. To compare this two dictionaries I use isEqualToDictionary: method. The documentation on isEqualToDictionary:says

如果两个词典具有相同的条目数，对于给定的键，每个字典中相应的值对象满足isEqual：test。

"Two dictionaries have equal contents if they each hold the same number of entries and, for a given key, the corresponding value objects in each dictionary satisfy the isEqual: test."

所以，我的字符串由 isEqual：

So, my strings are compared by isEqual: method.

问题是：

如何 isEqual：工作 NSString ？

The question is:
How does isEqual: work for the NSString?

是否使用 isEqual：从 NSObject ？
我已经读过 isEqual 从 NSObject 只是比较地址，使用 = = 。
为了证明或反驳这个想法，我写了一个例子：

Does it use isEqual: from NSObject? I've read that isEqual from NSObject just compares addresses, using ==. To prove or disprove this idea I wrote a sample:

NSString *str1 = @"sampleString";
NSString *str2 = [NSString stringWithFormat:@"%@", @"sampleString"];
BOOL result = [str1 isEqual:str2];

结果是 YES ，但是 str1 和 str2 的地址不同。

所以，它不使用 isEqual：从 NSObject （什么？或 NSObject 的 isEqual：执行比检查地址相等更复杂的操作。

The result is YES, the addresses of str1 and str2 are different though.
So, either it does not use isEqual: from NSObject (what than?), or NSObject's isEqual: does something more complicated then just checking equality of addresses.

有人知道它是如何工作的？

Does anybody know how does it really work?

推荐答案

NSString 覆盖 isEqual：以正确比较字符串，所以你可以这样比较字典。

NSString overrides isEqual: to properly compare strings, so you're perfectly fine to comparing dictionaries this way.

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