在java中两个集合之间的对称差异是什么最好的方法是什么？ [英] What is the best way get the symmetric difference between two sets in java?

问题描述

我想知道是否有一个快速/干净的方法来得到两组之间的差异？

我有：

 设置< String> s1 = new HashSet< String>（）; 
 s1.add（a）; 
 s1.add（b）; 
 s1.add（c）; 
 
设置< String> s2 = new HashSet< String>（）; 
 s2.add（b）; 
  

我需要像：

 设置< String> diff = Something.diff（s1，s2）; 
 // diff将包含[a，c] 
  

---

只是为了澄清我需要对称的区别。

解决方案

可以使用 Google Guava 媒体库中的一些功能（这真的很棒，我强烈推荐！）： / p>

  Sets.difference（s1，s2）; 
 Sets.symmetricDifference（s1，s2）; 
  

Javadocs difference（）和symmetricDifference()

symmetricDifference（）完全您要求的内容，但 difference（）也常常有帮助。

两个方法都返回一个实时视图，但是你可以在结果集上调用 .immutableCopy（）来获得一个不变的集合。如果你不想要一个视图，但需要一个set实例，你可以修改，调用 .copyInto（s3）。有关这些方法，请参见 SetView 。 p>

I'm wondering if there is a quick/clean way to get the difference between two sets ?

I have:

Set<String> s1 = new HashSet<String>();
s1.add("a");
s1.add("b");
s1.add("c");

Set<String> s2 = new HashSet<String>();
s2.add("b");

I need something like:

Set<String> diff = Something.diff(s1, s2);
// diff would contain ["a", "c"]

---

Just to clarify I need the symmetric difference.

解决方案

You can use some functions from the Google Guava library (which is really great, I strongly recommend it!):

Sets.difference(s1, s2);
Sets.symmetricDifference(s1, s2);

Javadocs for difference() and symmetricDifference()

symmetricDifference() does exactly what you are asking for, but difference() is also often helpful.

Both methods return a live view, but you can for example call .immutableCopy() on the resulting set to get a non-changing set. If you don't want a view, but need a set instance you can modify, call .copyInto(s3). See SetView for these methods.

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