如何优雅地交换地图中的键和值 [英] How to swap keys and values in a Map elegantly

问题描述

我已经知道如何做到这一点，让它工作 - 迭代的条目和交换手动。但我想知道，像这么多的任务，这一个可以解决在一个更优雅的方式。

I already know how to do it the hard way and got it working - iterating over entries and swapping "manually". But i wonder if, like so many tasks, this one can be solved in a more elegant way.

我读过这篇文章，不幸的是它没有优雅的解决方案。我也不可能使用任何奇特的Guava BiMaps或jdk之外的任何东西（项目堆栈已经定义）。

I have read this post, unfortunately it does not feature elegant solutions. I also have no possibility to use any fancy Guava BiMaps or anything outside the jdk (project stack is already defined).

我可以假设我的地图是双射的，btw： ）

I can assume that my map is bijective, btw :)

推荐答案

标准API / Java运行时不提供双向映射，所以唯一的解决方案是迭代所有条目并手动交换。

The standard API / Java runtime doesn't offer a bi-directional map, so the only solution is to iterate over all entries and swap them manually.

你可以做的是创建一个包含两个映射的包装类，并且执行一个双重 put（）在内部，所以你有两个视图上的数据。

What you can do is create a wrapper class which contains two maps and which does a dual put() internally so you have fast two views on the data.

此外，由于开源，你不必包括第三方库，您可以简单地将您需要的类复制到自己的项目中。

Also, thanks to open source, you don't have to include a third party library, you can simply copy the classes you need into your own project.

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