Python isinstance返回false习俗课

问题描述

我写了以下代码

class Mammal:
    def info():
        return 'I have fur on my body.'

    def identity_mammal():
        print('I am a mammal')

class Primate(Mammal):
    def info():
        return Mammal.info() + ' I have a large brain.'

    def identity_primate():
        print('I am a primate')

class Ape(Primate):
    def info():
        return Primate.info() + ' I am monkey oooh oooh aaah aaah.'

    def identity_ape():
        print('I am an ape')

class Human(Primate):
    def info():
        return Primate.info() + ' I am human,me bipedal SMART monkey'

    def identity_human():
        print('I am a human')

John = Human

print(isinstance(John,Mammal))
print(isinstance(John,Primate))
print(isinstance(John,Human))
print(isinstance(John,Ape))

这是一个关于继承的简单任务,但是当我使用isinstance函数时,我刚刚创建的Human实例似乎不是人类

[iveris@ic-rh7mnifi-105 oblig44]$ python3 inheritance.py 

False
False
False
False

解决方法

要创建实例,您需要使用括号:

John = Human()

print(isinstance(John,Mammal))
print(isinstance(John,Primate))
print(isinstance(John,Human))
print(isinstance(John,Ape))