import abc

class SetterGetter(object):
    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def set_val(self, inp):
        return

    @abc.abstractmethod
    def get_val(self):
        return

class TryAbsMethod(SetterGetter):
    def get_val(self):
        return self.inp

    def set_valz(self, inp):
        self.inp = inp

a = TryAbsMethod()
print(a)


根据教程,我期望从上面的代码中得到好处,但是我却从python得到了输出,这很奇怪,有人可以解释一下为什么吗?

输出得到

/usr/bin/python3.4 /home/murtuza/MyCodes/abstract.py
<__main__.TryAbsMethod object at 0x7f93ba8ab048>

Process finished with exit code 0


预期的异常

TypeError: Can't instantiate abstract class TryAbsMethod with abstract method set_val

最佳答案

您正在使用Python3.x。在Python 3.x中,元类声明语法已更改。

class SetterGetter(object, metaclass=abc.ABCMeta):  # <---
    @abc.abstractmethod
    def set_val(self, inp):
        return

    @abc.abstractmethod
    def get_val(self):
        return


请参见Customizing class creation - Data model - Python 3.x documentationPEP3115 - Metaclasses in Python 3

关于python - python中的抽象方法,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/32431272/

10-12 00:18
查看更多