NSSet的containsObject：测试指针相等还是值相等？ [英] Does NSSet's containsObject: test for pointer equality or value equality?

问题描述

说我有一个 NSSet ，里面有一个字符串。如果我发送 containsObject：与另一个字符串，它是一个不同的指针，但完全相同的字符串值，将返回 YES ？

此外，对于 removeObject：来说，

解决方案

-containsObject：不同的对象有不同的指针但是相同的字符串值会导致删除？ 使用 -isEqual：（和 -hash ）进行相等测试。这也适用于 -removeObject：以及 NSSet 中的任何其他操作，这取决于一些相等的概念。 / p>

Say I have an NSSet with a string in it. If I send containsObject: with another string which is a different pointer but the exact same string value, will that return YES?

Also, is it the same story when it comes to removeObject:? I.e., different objects with different pointers but the same string values will cause removal?

解决方案

-containsObject: uses -isEqual: (and -hash) for equality testing. This applies to -removeObject: as well, and any other operations in NSSet that depend on some notion of equality.

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