python子类继承父类的类方法时,类方法用的return返回值,子类继承后调用返回的就是空值,而不是父类方法应有的返回值。我把return改成打印值,这样子类继承后调用返回的就不是空值了,这是为什么呀?
```就是下面这个代码
class father():
def __init__(self):
self.live = 8
def speak(self):
return 23
class son(father):
def speak(self):
super().speak()
a = father()
p = son()
print(a.speak())
print(p.speak())
```返回结果:
23
None
```把return改了后代码:
class father():
def __init__(self):
self.live = 8
def speak(self):
print(23)
class son(father):
def speak(self):
super().speak()
a = father()
p = son()
a.speak()
p.speak()
```改后结果
23
23