如何找到两个HashSet的补充

Question

我有两个HashSet - setA和setB。

1. 我们怎样才能找到setA和setB的补充？
2. 交叉代码是找到交集的最佳方法吗？

CODE

 string stringA = "A,B,A,A";
 string stringB = "C,A,B,D";

 HashSet<string> setA = new HashSet<string>(stringA.Split(',').Select(t => t.Trim()));
 HashSet<string> setB = new HashSet<string>(stringB.Split(',').Select(t => t.Trim()));

 //Intersection - Present in A and B
 HashSet<string> intersectedSet = new HashSet<string>( setA.Intersect(setB));

 //Complemenet - Present in A; but not present in B

更新：

使用OrdianlIgnoreCase忽略案例敏感性How to use HashSet<string>.Contains() method in case -insensitive mode?

参考：

1. What is the difference between HashSet<T> and List<T>?
2. Intersection of multiple lists with IEnumerable.Intersect()
3. Comparing two hashsets
4. Compare two hashsets?
5. Quickest way to find the complement of two collections in C#

Answer 1

  

1 - 我们如何找到setA和setB的补充？

使用HashSet<T>.Except Method

//Complemenet - Present in A; but not present in B
HashSet<string> ComplemenetSet = new HashSet<string>(setA.Except(setB));

尝试使用以下字符串。

string stringA = "A,B,A,E";
string stringB = "C,A,B,D";

ComplementSet将包含E

  

2 - 交叉点的代码是找到交叉点的最佳方法吗？

可能，是

Answer 2

您可以使用Except获取A或B的补码。要获得对称补码，请使用SymmetricExceptWith。

setA.SymmetricExceptWith(setB);

请注意，此修改了 setA。要获得交集，有两种方法：Intersect，用于创建新的HashSet，IntersectWith，用于修改第一个：

// setA and setB unchanged
HashSet<string> intersection = setA.Intersect(setB);

// setA gets modified and holds the result
setA.IntersectWith(setB);