Python类inheriten

Question

Possible Duplicate:
subclass __init__ overrides superclass’s

class A():
    z = 'z it is'
    def __init__(self):
        self.a = 'a it is'

class B(A):
    def __init__(self):
        self.b = 'b it is'

b = B()
print b.z # z it is 
print b.a # AttributeError: B instance has no attribute 'a'

b是从A类继承的B类的实例。这不意味着我可以访问父类的属性吗？你知道吗

Answer 1

您需要显式地调用超类__init__。它不会自动调用。你知道吗

Answer 2

类B中的__init__函数应该这样编写：

class B(A):
    def __init__(self):
        A.__init__(self)
        self.b = "b it is"