Question

From what I understand about the where clause in LINQ, it combines elements from two or more sets based on all possible combinations of each element and then applies the criteria. For example:

public static void Main(string[] args)
{
    var setA = new[] {3, 4, 5};
    var setB = new[] {6, 7, 8};

    var result = from a in setA
                 from b in setB
                 let sum = a + b
                 where sum == 10            // Where, criteria sum == 10.
                 select new {a, b, sum};

    foreach (var element in result)
        Console.WriteLine("({0},{1}) == {2}", element.a, element.b, element.sum);

    Console.ReadLine();
}

This produces the following results before the where criteria is applied.

3,6 = 9    4,6 = 10    5,6 = 11
3,7 = 10   4,7 = 11    5,7 = 12
3,8 = 11   4,8 = 12    5,8 = 13

The results that match the criteria are 3,7 and 4,6. This produces the results:

(3,7) == 10
(4,6) == 10

However, from what I remember in grade school set theory, is there a way to provide the union of the two sets (pseudocode):

{3, 4, 5} union {6, 7, 8} = {3, 4, 5, 6, 7, 8}

Thanks,

Scott

Answer 1

var Result = setA.Union(setB)

For a full listing of all the operators, look at Enumerable.