如何在LINQ中按列表合并分组 [英] How to merge group by list in LINQ

问题描述

我的列表结构为:List<KeyValuePair<string, List<int>>

键值对下面的列表

Key       Values
[PageA] [1, 3, 4] 
[PageA] [1, 3, 5] 
[PageA] [1, 3, 4, 5, 6]
[PageB] [1, 3, 4, 6] 
[PageC] [1, 3, 4] 
[PageC] [1, 3, 4, 5, 7]

问::如何合并相同键的所有值，还删除重复项，如下所示.

Q: How do i merge all values for the same keys, also removing duplicates as well, like below.

[PageA] [1, 3, 4, 5, 6]
[PageB] [1, 3, 4, 6] 
[PageC] [1, 3, 4, 5, 7]

我试图先将它们分组，然后再将它们分组，但是我无法将它们进一步合并为单个键.

I am trying to group them first, which groups them fine but I am unable to merge those further into single keys.

var pages = pageData.GroupBy(p => p.Key)

推荐答案

按Key分组后，应使用SelectMany合并从不同记录中获得的所有集合.这样做之后，您可以调用Distinct.

After grouping by your Key you should use SelectMany to merge all the collection you got from the different records. After doing so you can call Distinct.

var result = pageData.GroupBy(item => item.Key)
                     .Select(group => new 
                     { 
                         Key = group.Key, 
                         Values = group.SelectMany(item => item.Value).Distinct().ToList() 
                     }).ToList();

其他.ToList()都在其中，以便于调试

The additional .ToList()s are just there to ease in debug

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