Question

How can I do this by lambda? To find out whether the two lists have the same value(s).

    void Main()
    {
        var list1 = new List<string>{
            "a", "b", "c"
        };

        var list2 = new List<string>{
            "c", "d", "e"
        };

        bool listsHaveSameValue = false;
        foreach(var list1Value in list1){
              listsHaveSameValue = list2.Any(c => c.Equals(list1Value));
              if(listsHaveSameValue){
                   break;
              }
        }

        Debug.WriteLine(listsHaveSameValue.ToString());
    }

Answer 1

You should look into Intersect.

var list1 = new List<string>{ "a", "b", "c"};
var list2 = new List<string>{ "c", "d", "e"};

var doubles = list1.Intersect(list2);
bool listsHaveSameValue = doubles.Any();

Actually there is no real need to use a lambda (as you’ve asked).