How to intersect mutliple list with Lambda Expression?

Question

I have a few list. Their count isn't clear.

For example (for 4 list):

List1   List2    List3     List4 
-----   -----    -----     -----
  1       2        3         4
  2       4        8         3   
  3       8        4         5   
  4       11       6         1    
  5       3        7         7    
  6       9        11        9

I want to find the items that are common. It can do with T-SQL in MSSQL.

The result will be like that:

ResultList : (3, 4)

How is it done with Lambda Expression ?

score 5 · Accepted Answer · answered Jun 28 '12 at 20:28

5

You can use Enumerable.Intersect

var commonItems = list1.Intersect(list2).Intersect(list3).Intersect(list4);

answered Jun 28 '12 at 20:28

Reed Copsey

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score 2 · Answer 2 · answered Jun 28 '12 at 20:41

2

For an arbitrary number of lists, you would do something like this:

var List<List<int>> lists; //This contains the lists I assume...
var result = lists.Skip(1).Aggregate(lists.First(), (accum, cur) => accum.Intersect(cur));

answered Jun 28 '12 at 20:41

GregRos

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Thanks @GregRos, I already had the intersection solved but was about ready to do some hardcoding for arbitrary number of lists. This was just the piece I was missing. – Fjarskiptagervitungl Nov 24 '15 at 08:32

score 1 · Answer 3 · answered Jun 28 '12 at 20:28

1

list1.Intersect(list2).Intersect(list3).Intersect(list4);

answered Jun 28 '12 at 20:28

willvv

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score 0 · Answer 4 · answered Jun 28 '12 at 20:28

0

Are you looking for Intersect?

answered Jun 28 '12 at 20:28

qJake

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score 0 · Answer 5 · answered Jun 28 '12 at 20:29

0

You can use Enumerable.Intersect and intersect List1 with List1 and its result with List3 and so on.

    List1.Intersect(List2).Intersect(List3).Intersect(List4)

answered Jun 28 '12 at 20:29

Ani

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How to intersect mutliple list with Lambda Expression?

5 Answers5