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这些是创建抽象基类并将其注册到具体类的不同方法：

进口：

from abc import ABCMeta
from abc import ABC
from abc import abstractmethod

方法一：

>>> class A(metaclass=ABCMeta): 
...     @abstractmethod
...     def hello(self):
...         return
... 
>>> class B(A):
...     def hello(self):
...         print("Hello World!")
... 
>>> b = B()
>>> b.hello()
Hello World!
>>> 
>>> print(B.__mro__)
(<class '__main__.B'>, <class '__main__.A'>, <class 'object'>)

方法二：

>>> class A(object): 
...     __metaclass__ = ABCMeta
...     
...     @abstractmethod
...     def hello(self):
...         return
... 
>>> class B(A):
...     def hello(self):
...         print("Hello World!")
... 
>>> b = B()
>>> b.hello()
Hello World!
>>> 
>>> print(B.__mro__)
(<class '__main__.B'>, <class '__main__.A'>, <class 'object'>)

方法三：

>>> class A(ABC): 
...     @abstractmethod
...     def hello(self):
...         return
... 
>>> class B(A):
...     def hello(self):
...         print("Hello World!")
... 
>>> b = B()
>>> b.hello()
Hello World!
>>> 
>>> print(B.__mro__)
(<class '__main__.B'>, <class '__main__.A'>, <class 'abc.ABC'>, <class 'object'>)

方法四：

>>> class A(metaclass=ABCMeta): 
...     @abstractmethod
...     def hello(self):
...         return
... 
>>> class B(object):
...     def hello(self):
...         print("Hello World!")
... 
>>> A.register(B)
<class '__main__.B'>
>>> 
>>> b = B()
>>> b.hello()
Hello World!
>>> 
>>> print(B.__mro__)
(<class '__main__.B'>, <class 'object'>)

方法五：

>>> class A(ABC): 
...     @abstractmethod
...     def hello(self):
...         return
... 
>>> class B(object):
...     def hello(self):
...         print("Hello World!")
... 
>>> A.register(B)
<class '__main__.B'>
>>> 
>>> b = B()
>>> b.hello()
Hello World!
>>> 
>>> print(B.__mro__)
(<class '__main__.B'>, <class 'object'>)

问题：

  1. 除了MRO，它们之间有什么区别？
  2. 他们有不同的用例吗？
  3. 在他们之间是否有一种首选或更 Pythonic 的方式来做到这一点？

PS：请注意，只有 #2 也适用于 Python 2

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0 回答 0