How would you do a “not in” query with Linq?

var matches = from item1 in list1
join item2 in list2 on item1.Email equals item2.Email
select new { Email = list1.Email };

NorthwindDataContext dc = new NorthwindDataContext();
dc.Log = Console.Out;

var query =
    from c in dc.Customers
    where !(from o in dc.Orders
            select o.CustomerID)
           .Contains(c.CustomerID)
    select c;

foreach (var c in query) Console.WriteLine( c );

var answer = list1.Except(list2);

from item1 in List1
where !(list2.Any(item2 => item2.Email == item1.Email))
select item1;

var itemIds = inMemoryList.Select(x => x.Id).ToArray();
var otherObjects = context.ItemList.Where(x => !itemIds.Contains(x.Id));

var secondEmails = (from item in list2
                    select new { Email = item.Email }
                   ).ToList();

var matches = from item in list1
              where !secondEmails.Contains(item.Email)
              select new {Email = item.Email};

List<int> list1 = new List<int>();
// fill data
List<int> list2 = new List<int>();
// fill data

var results = from i in list1
              where !list2.Contains(i)
              select i;

foreach (var result in results)
    Console.WriteLine(result.ToString());

'Then get the Item Mappings Present for the branch
        Dim _adpt As New gItem_BranchesTableAdapter
        Dim dt As New ds_CA_HO.gItem_BranchesDataTable
        _adpt.FillBranchMappings(dt, BranchId)

        Dim _MappedItems As List(Of LocalItem) = (From _item As LocalItem In _AllItems Join _
                                       dr As ds_CA_HO.gItem_BranchesRow In dt _
                                       On _item.Id Equals dr.numItemID _
                                     Select _item).ToList

        _AllItems = _AllItems.Except(_MappedItems.AsEnumerable).ToList


        Return _AllItems

var linked =
  from x in dc.X
  from y in dc.Y
  where x.MyProperty == y.MyProperty
  select x;
var notLinked =
  dc.X.Except(linked);

class Program
{
    static void Main(string[] args)
    {
        // creates some foos
        List<Foo> fooList = new List<Foo>();
        fooList.Add(new Foo { Id = 1, BarId = 11 });
        fooList.Add(new Foo { Id = 2, BarId = 12 });
        fooList.Add(new Foo { Id = 3, BarId = 13 });
        fooList.Add(new Foo { Id = 4, BarId = 14 });
        fooList.Add(new Foo { Id = 5, BarId = -1 });
        fooList.Add(new Foo { Id = 6, BarId = -1 });
        fooList.Add(new Foo { Id = 7, BarId = -1 });

        // create some bars
        List<Bar> barList = new List<Bar>();
        barList.Add(new Bar { Id = 11 });
        barList.Add(new Bar { Id = 12 });
        barList.Add(new Bar { Id = 13 });
        barList.Add(new Bar { Id = 14 });
        barList.Add(new Bar { Id = 15 });
        barList.Add(new Bar { Id = 16 });
        barList.Add(new Bar { Id = 17 });

        var linked = from foo in fooList
                     from bar in barList
                     where foo.BarId == bar.Id
                     select foo;
        var notLinked = fooList.Except(linked);
        foreach (Foo item in notLinked)
        {
            Console.WriteLine(
                String.Format(
                "Foo.Id: {0} | Bar.Id: {1}",
                item.Id, item.BarId));
        }
        Console.WriteLine("Any key to continue...");
        Console.ReadKey();
    }
}

class Foo
{
    public int Id { get; set; }
    public int BarId { get; set; }
}

class Bar
{
    public int Id { get; set; }
}

var items = FileMaintenanceBusiness.Instance.GetAllCodes();
            var result = (from i in items select i.Code).Max();
            List<int> countLIst = new List<int>();
            for (int i = 1; i <= result; i++)
            {
                countLIst.Add(i);
            }
            var query =
            from c in countLIst
            where !(from o in items
                    select o.Code)
                   .Contains(c)
            select c;


            int minID= (from q in query select q).Min();
            ID = minID;