从父类获取所有子模型 - Django

Question

如何从父类中获取所有子模型？作为一个例子，我有：

class Device(PolymorphicModel):

   .....

class Mobile(Device): 

   .....

class Computer(Device):

   .....

所以我想从 Device 模型中获取它的所有后代：Mobile、Computer 作为类而不是实例。

谢谢你。

Answer 1

您可以使用[Python-doc]方法获取直接子类：class.__subclasses__()>>> Device.__subclasses__()[<class 'Mobile'>, <class 'Computer'>]然而，这些也可能有子类。我们可以开发一个每次都获得下一代的算法，并一直这样做直到找不到新的子类，例如：def get_descendants(klass):&nbsp; &nbsp; gen = { klass }&nbsp; &nbsp; desc = set()&nbsp; &nbsp; while gen:&nbsp; &nbsp; &nbsp; &nbsp; gen = { skls for kls in gen for skls in kls.__subclasses__() }&nbsp; &nbsp; &nbsp; &nbsp; desc.update(gen)&nbsp; &nbsp; return desc或使用可变数量的参数：def get_descendants(*klass):&nbsp; &nbsp; gen = { *klass }&nbsp; &nbsp; desc = set()&nbsp; &nbsp; while gen:&nbsp; &nbsp; &nbsp; &nbsp; gen = { skls for kls in gen for skls in kls.__subclasses__() }&nbsp; &nbsp; &nbsp; &nbsp; desc.update(gen)&nbsp; &nbsp; return desc这将返回一个set()包含所有后代（直接和间接）的。