为什么没有SortedList< T>在.NET中？ [英] Why is there no SortedList<T> in .NET?

问题描述

为什么只有 SortedList< TKey，TValue> 看起来更像是字典，却没有 SortedList< T> 实际上只是始终排序的列表吗？

Why is there only a SortedList<TKey, TValue> which looks more like a dictionary, but no SortedList<T> that is actually just a list that is always sorted?

根据有关SortedList的MSDN文档，它实际上在内部实现为 KeyValuePair< TKey，TValue> 始终按键排序。同一类作为 T 类型的列表是否有用？

According to the MSDN documentation on SortedList, it is actually internally implemented as a dynamically-sized array of KeyValuePair<TKey, TValue> that is always sorted by the key. Wouldn’t the same class be more useful as a list of any type T? Wouldn’t that fit the name better, too?

推荐答案

尽管没有人能真正告诉您为什么没有 SortedList< T> ，可以讨论为什么 SortedList 需要一个键和一个值。字典将键映射到值。典型的方法是使用二叉树，哈希表和列表（数组），尽管哈希表最常见，因为它们在大多数操作中都是O（1）。

Although nobody can really tell you why there is no SortedList<T>, it is possible to discuss why SortedList takes a key and a value. A dictionary maps keys to values. The typical ways to do this are with a binary tree, a hash table, and a list (array), though hash tables are most common because they are O(1) for most operations.

O（1）中不支持的主要操作是按顺序获取下一个键。如果您希望这样做，通常可以使用二叉树，为您提供排序字典。

The primary operation that it doesn't support in O(1) is getting the next key in order. If you want to be able to do that, you typically use a binary tree, giving you a sorted dictionary.

如果您决定将地图实现为列表，则可以将使元素按键排序，以便查找为O（lg n），从而为您提供另一个排序字典-以排序列表的形式。当然已经使用了名称 SortedDictionary ，但没有使用 SortedList 。我可能将其称为 SortedListDictionary 或 SortedDictionaryList ，但我没有给它命名。

If you decide to implement the map as a list, you would keep the elements sorted by key so that lookup is O(lg n), giving you another sorted dictionary -- in the form of a sorted list. Of course the name SortedDictionary was already taken, but SortedList wasn't. I might have called it SortedListDictionary or SortedDictionaryList, but I didn't get to name it.

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