什么是从一个字典中的值和键复制到另一个在C＃中最快的方法是什么？ [英] What's the fastest way to copy the values and keys from one dictionary into another in C#?

问题描述

似乎没有成为一个dictionary.AddRange（）方法。有谁知道一个更好的方式来复制项目到另一个词典不使用foreach循环。

There doesn't seem to be a dictionary.AddRange() method. Does anyone know a better way to copy the items to another dictionary without using a foreach loop.

我使用的System.Collections.Generic.Dictionary。这是.NET 2.0。

I'm using the System.Collections.Generic.Dictionary. This is for .NET 2.0.

推荐答案

有没有错，一个用于/ foreach循环。这就是一个假设的AddRange方法，无论如何都会做的。

There's nothing wrong with a for/foreach loop. That's all a hypothetical AddRange method would do anyway.

唯一的额外关注我不得不与内存分配行为，因为加入了大量条目可能会导致多次重新分配并重新散列。没有办法通过一个给定的量，以增加现有的字典的容量。你可能会更好分配与足够的能力为当前的人一个新的字典，但你还是需要一个循环加载它们中的至少一个。

The only extra concern I'd have is with memory allocation behaviour, because adding a large number of entries could cause multiple reallocations and re-hashes. There's no way to increase the capacity of an existing Dictionary by a given amount. You might be better off allocating a new Dictionary with sufficient capacity for both current ones, but you'd still need a loop to load at least one of them.

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