更改地图的迭代顺序

Question

How can I iterate over a Map in a specific desired order? I currently have a HashMap and want to be able to define a specific iteration order. The order should be able to get changed by the user.

My first thought was to use a LinkedHashMap since that one will give me an order of entries, but sadly the implementation only orders them by order of insertion or by order of access. Other than manipulating the insertion order with deletes, I dont see the LinkedHashMap fit for the task. Imo the implementation kind of falls short of what the docs say about it.

I also found the SortedMap, but that one uses a comparator, so I needs to evaluate that every time I want to iterate over the entries. This could be a solution, but is kind of expensive: O(n*log(n)).

So far Andreas comment seems to be the best solution, which is having both a HashMap and a ArrayList.

Answer 1

Convert the LinkedHashMap to an ArrayList and then switch the value. Then convert back to LinkedHashMap. O(n) for both space and time complexity.

Answer 2

这个问题的正确答案是您使用了不正确的数据结构，因此必须重新排序。

Answer 3

如果您想要一个键值对，并且希望它具有ArrayList的属性，那么您可以尝试

List<Pair<String, String>> ?