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如何合并列表>在 C# 中

发布于 2024-10-09 05:27:30 字数 392 浏览 1 评论 0 原文

我有一个 List>，其中包含

{  {"A" , "B" }, 
   {"C" , "D" }
}

我需要将所有内部列表合并到另一个列表中，

因此生成的 List 将包含

     {"A","B","C","D"}

现在我使用for循环来执行此操作

有没有办法使用LINQ或Lambda表达式来执行此操作。

请帮助我做到这一点。

提前致谢。

原文

I'm having a List<List<String>>, and which contains

{  {"A" , "B" }, 
   {"C" , "D" }
}

I need to union all the innerlist into another list

So the resulting List<String> will contain

     {"A","B","C","D"}

Now im using for loop to do this

Is there any way to do this Using LINQ or Lambda Expression.

Please help me to do this.

Thanks in advance.

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謸气贵蔟 2024-10-16 05:27:30

不完全是一个联盟，但你可以尝试这个

YourList.SelectMany(l=>l).Distinct()

Not Exactly a Union, but you can try this

YourList.SelectMany(l=>l).Distinct()

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始终不够 2024-10-16 05:27:30

List<List<string>> collections = new List<List<string>>()
        {
          new List<string>(){"A" , "B" }, 
          new List<string>() {"C" , "D" }
        };

var list = collections.SelectMany(x => x).ToList();

SelectMany 构建一个表达式树，在计算时将列表列表展平为组合成员的单个列表。

ToList 强制计算表达式树并生成一个列表。

如果要消除重复项，可以在调用“ToList()”之前添加 Distinct 调用

List<List<string>> collections = new List<List<string>>()
        {
          new List<string>(){"A" , "B" }, 
          new List<string>() {"C" , "D" }
        };

var list = collections.SelectMany(x => x).ToList();

SelectMany builds up a expression tree that when evaluated flattens the list of list to a single list of combined members.

ToList forces the expression tree to be evaluated and which results in a List.

If you want to eliminate duplicates you can add a Distinct call before the call to 'ToList()'

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浮萍、无处依 2024-10-16 05:27:30

您可以使用 SelectMany 扩展方法。

List<List<String>> masterList = { {"A" , "B" }, {"C" , "D" } };

IEnumerable<string> results = masterList.SelectMany(l => l);

You can use the SelectMany extension method.

List<List<String>> masterList = { {"A" , "B" }, {"C" , "D" } };

IEnumerable<string> results = masterList.SelectMany(l => l);

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哆兒滾 2024-10-16 05:27:30

var result = myLists.SelectMany(l => l);

var result = myLists.SelectMany(l => l);

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浊酒尽余欢 2024-10-16 05:27:30

聚合怎么样？

myLists.Aggregate((left, right) => left.Union(right));

对我来说，这比使用 SelectMany 更具表现力，因为它准确地告诉您在做什么：通过对所有列表调用 union 来聚合列表列表。

How about Aggregate?

myLists.Aggregate((left, right) => left.Union(right));

To me, this is more expressive than using SelectMany, because it is telling you exactly what you are doing: Aggregate your list of lists by calling union on them all.

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为你拒绝所有暧昧 2024-10-16 05:27:30

只是为了好玩：

(from list in theList from e in list select e).Distinct().ToList()

这当然与 @Alexander Taran 的解决方案相同，只是使用查询语法而不是 lambda 语法。（或者至少应该是 – 我手边没有 LINQPad。）

Just for kicks:

(from list in theList from e in list select e).Distinct().ToList()

This is of course the same solution as @Alexander Taran's, just with query syntax instead of lambda syntax. (Or at least it should be – I don't have my LINQPad handy.)

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