订购哈希集示例？

发布于 2024-09-12 07:00:57 字数 190 浏览 7 评论 0 原文

我需要一个关于如何在 HashSet 上使用类似类来获取升序的示例。假设我有一个像这样的 HashSet：

HashSet<String> hs = new HashSet<String>();

如何让 hs 按升序排列？

原文

I need an example on how to use a comparable class on a HashSet to get an ascending order. Let’s say I have a HashSet like this one:

HashSet<String> hs = new HashSet<String>();

How can I get hs to be in ascending order?

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執念 2024-09-19 07:00:57

使用 TreeSet 相反。它有一个带有Comparator的构造函数。它会自动对 Set 进行排序。

如果您想将 HashSet 转换为 TreeSet，请执行以下操作：

Set<YourObject> hashSet = getItSomehow();
Set<YourObject> treeSet = new TreeSet<YourObject>(new YourComparator());
treeSet.addAll(hashSet);
// Now it's sorted based on the logic as implemented in YourComparator.

如果您拥有的项目本身已经实现了 Comparable 并且它的默认排序顺序已经是你想要的，那么你基本上不需要提供比较器。然后，您可以直接基于 HashSet 构造 TreeSet。例如，

Set<String> hashSet = getItSomehow();
Set<String> treeSet = new TreeSet<String>(hashSet);
// Now it's sorted based on the logic as implemented in String#compareTo().

另请参阅：

Use a TreeSet instead. It has a constructor taking a Comparator. It will automatically sort the Set.

If you want to convert a HashSet to a TreeSet, then do so:

Set<YourObject> hashSet = getItSomehow();
Set<YourObject> treeSet = new TreeSet<YourObject>(new YourComparator());
treeSet.addAll(hashSet);
// Now it's sorted based on the logic as implemented in YourComparator.

If the items you have itself already implements Comparable and its default ordering order is already what you want, then you basically don't need to supply a Comparator. You could then construct the TreeSet directly based on the HashSet. E.g.

Set<String> hashSet = getItSomehow();
Set<String> treeSet = new TreeSet<String>(hashSet);
// Now it's sorted based on the logic as implemented in String#compareTo().