What is the linq equivalent to the SQL IN operator

Question

With linq I have to check if a value of a row is present in an array.
The equivalent of the sql query:

WHERE ID IN (2,3,4,5)

How can I do it?

Answer 1

A very basic example using .Contains()

List<int> list = new List<int>();
for (int k = 1; k < 10; k++)
{
    list.Add(k);
}

int[] conditionList = new int[]{2,3,4};

var a = (from test in list
         where conditionList.Contains(test)
         select test);

Answer 2

Intersect and Except are a little more concise and will probably be a bit faster too.

IN

collection.Intersect(new[] {2,3,4,5});

NOT IN

collection.Except(new[] {2,3,4,5});

or

Method syntax for IN

collection.Where(x => new[] {2,3,4,5}.Contains(x));

and NOT IN

collection.Where(x => !(new[] {2,3,4,5}.Contains(x)));