About [NSArray containsObject:]

最新推荐文章于 2021-08-02 21:27:53 发布

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最新推荐文章于 2021-08-02 21:27:53 发布

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本文详细解释了在Swift中使用NSArray的containsObject:方法时，为何会误将对象的引用进行比较，而不是其实际值。并提供了解决方案，包括使用collection.contains或者覆盖NSObject的isEqual方法。

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he documentation for [NSArray containsObject:] says:

This method determines whether anObject is present in the receiver by sending an isEqual: message to each of the receiver’s objects (and passing anObject as the parameter to each isEqual: message).

The documentation for [NSArray containsObject:] says:

This method determines whether anObject is present in the receiver by sending an isEqual: message to each of the receiver’s objects (and passing anObject as the parameter to each isEqual: message).

The problem is that you are comparing references to objects rather than the values of the objects. To make this specific example work, you will either need to send [collection containsObject:] an instance of a variable it contains (e.g. A, B, or C), or you will need to override the [NSObject isEqual:] method in your Fruit class.

转载：http://stackoverflow.com/questions/2941596/nsarray-containobjects-method