使用linq，如何從另一個IEnumerable <>的屬性創建IEnumerable <>

Question

我有一個清單：

IEnumerable<Person> people

我想得到這個：

IEnumerable<Dog> peoplesDogs

狗是人對象的財產，也是

 IEnumerable<Dog> 

Answer 1

var peoplesDogs = people.SelectMany(p => p.Dogs);

Answer 2

var peoplesDogs = from p in people 
                  from d in p.Dogs
                  select d;

Answer 3

var peopleDogs = people.Select(p => p.Dogs)

編輯

上面的代碼將創建IEnumerable<IEnumerable<Dog>>但顯然只需要IEnumerable<Dog> 。

就像在LukeH的答案中一樣，您需要使用SelectMany來展平：

var peopleDogs = people.SelectMany(p => p.Dogs)

Answer 4

你也可以

var peoplesDogs = from p in people
                  from d in p.Dogs
                  select d;

具有與以下相同的效果：

var peoplesDogs = people.SelectMany(p => p.Dogs)