Left join on two Lists and maintain one property from the right with Linq

Question

I have 2 lists of the same type. The left list:

var leftList = new List();
leftList.Add(new Person {Id = 1, Name = \"John\", Chang         


        

Answer 1

Well spender was faster then me, I did without any extension method.

Without any extension method:

List mergedList =  leftList
            .GroupJoin(
                rightList, left => left.Id, right => right.Id, 
                (x, y) => new { Left = x, Rights = y  }
            )
            .SelectMany(
                x => x.Rights.DefaultIfEmpty(),
                (x, y) => new Person
                {
                    Id = x.Left.Id, 
                    Name = x.Left.Name, 
                    Changed = y == null ? x.Left.Changed : y.Changed
                }
            ).ToList();

The GroupJoin makes left outer join operation.