ios - 有效地搜索集合中的 NSString

Question

考虑内存中的一组数千个 NSString 对象。

在集合中搜索特定 NSString 的最有效方法是什么？使用 NSDictionary 就足够了吗？还是保证 NSSet 的搜索是 O(1)(找不到任何说明如此的文档)？

同样的策略是否适用于 NSData 对象？

Answer 1

This page显示以下关于集合的注释:

Note: If the objects in the set have a good hash function, accessing an element, setting an element, and removing an element all take constant time. With a poor hash function (one that causes frequent hash collisions), these operations take up to linear time. Classes such as NSString that are part of Foundation have a good hash function.

因此，对于 NSString，您可以期望基于上述内容的恒定时间。