Apple给了我们一个向下转换相同类型对象的例子:letsomeObjects:[AnyObject]=[Movie(name:"2001:ASpaceOdyssey",director:"StanleyKubrick"),Movie(name:"Moon",director:"DuncanJones"),Movie(name:"Alien",director:"RidleyScott")]然后我们可以通过创建抽象变量“object”并将其转换为我们期望的(电影)来访问每个单独的属性:forobjectinsomeObjects{letmovie=objectas!Movieprint