Exclude items of one list in another with different object data types, LINQ?

Question

I have two lists filled with their own data. lets say there are two models Human and AnotherHuman. Each model contains different fields, however th

Answer 1

var duplicates = from h in humans
                 from a in anotherHumans
                 where (h.PersonalID == a.PersonalID) ||
                       (h.LastName == a.LastName && 
                        h.FirstName == a.FirstName && 
                        h.Birthday == a.Birthday)
                 select a;

anotherHumans = anotherHumans.Except(duplicates);

Answer 2

var nonIdItems = anotherHumans
   .Where(ah => !ah.PersonalID.HasValue)
   .Join(humans, 
         ah => new{ah.LastName, 
           ah.FirstName, 
           ah.Birthday}, 
         h => new{h.LastName, 
           h.FirstName, 
           h.Birthday}, 
         (ah,h) => ah);
var idItems = anotherHumans
   .Where(ah => ah.PersonalID.HasValue)
   .Join(humans, 
         ah => ah.PersonalID
         h => h.PersonalID, 
         (ah,h) => ah);
var allAnotherHumansWithMatchingHumans = nonIdItems.Concat(idItems);
var allAnotherHumansWithoutMatchingHumans = 
      anotherHumans.Except(allAnotherHumansWithMatchingHumans);

Answer 3

Instead of creating new objects, how about checking the properties as part of the linq query

List<Human> humans = _unitOfWork.GetHumans();
List<AnotherHuman> anotherHumans = _unitofWork.GetAnotherHumans();

// Get all anotherHumans where the record does not exist in humans
var result = anotherHumans
               .Where(ah => !humans.Any(h => h.LastName == ah.LastName
                               && h.Name == ah.Name
                               && h.Birthday == ah.Birthday
                               && (!h.PersonalId.HasValue || h.PersonalId == ah.PersonalId)))
               .ToList();