Select from Multiple lists where value exists in all

Asked Oct 25 '17 at 10:33

Active Oct 25 '17 at 10:36

Viewed 162 times

Looking for a way to select from multiple lists where values exists in all lists.

   public class A {
       public List<B> BList {get;set;}
   }

   public class B {
       public string Key {get;set;}
       public List<int> IntegerList {get;set;}
   }

Given the following input I would like to retrieve the integers that exist in all lists.

method(){
   List<int> list1 = new List<int>{ 1, 2, 3, 4, 5, 6};
   List<int> list2 = new List<int>{ 1, 2, 3 };
   List<int> list3 = new List<int>{ 1, 2 };

   var a = new A();

   a.BList = new List<B>{ new B { Key = "b1", IntegerList = list1, 
                          new B { Key = "b2", IntegerList = list2
                          new B { Key = "b3", IntegerList = list3 } 
}

I basically want to be able to retrieve a new list { 1,2 } given an infinite number of integer lists, since these values appear in all.

asked Oct 25 '17 at 10:33

jjharrison

In the marked duplicate look at the answer with the highest number of votes, not the accepted answer. – Igor Oct 25 '17 at 10:36
@Igor This answers the question but my problem is I do not know how many Integer lists. Cannot just assume I'm intersecting two lists – jjharrison Oct 25 '17 at 10:41
1

@jjharrison, take a look - https://dotnetfiddle.net/mcOrVO – Artavazd Balayan Oct 25 '17 at 10:45
The answer remains is the same as in the marked duplicate(s) but you use a loop to iterate over your lists and keep on intersecting. – Igor Oct 25 '17 at 10:48
@Igor I was able to do this by using the aggregate linq function to iterate the list of lists. – jjharrison Oct 25 '17 at 11:20
Glad to hear it. – Igor Oct 25 '17 at 11:24

Select from Multiple lists where value exists in all

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