Python抽象类的新写法

class MyCls():
  def foo(self):
    print('method no implement')

运行的例子


> a = MyCls()
> a.foo()
method no implement
>

class MyCls():
  def foo(self):
    raise Exception('no implement exception', 'foo method need implement')

> a = MyCls()
> a.foo()
Traceback (most recent call last):
 File "<interactive input>", line 1, in <module>
 File "<clipboard>", line 3, in foo
Exception: ('no implement exception', 'foo method need implement')

from abc import ABCMeta
 
from abc import ABCMeta,abstractmethod
 
class Foo():
  __metaclass__ = ABCMeta
  @abstractmethod
  def bar(self):
    pass

> class B(Foo):
... def bar(self):
... pass
... 
> B()
<__main__.B object at 0x02EE7B50>
> B().bar()
> class C(Foo):
... pass
... 
> C().bar()
Traceback (most recent call last):
 File "<interactive input>", line 1, in <module>
TypeError: Can't instantiate abstract class C with abstract methods bar
>