通过超级调用父类与父类名称之间的区别？

Question

In the code:

class Mother(object):
    def __init__(self):
        self._haircolor = "Brown"

class Child(Mother):
    def __init__(self): 
        #Mother.__init__(self)
        super(Mother, self).__init__(self)

    def print_haircolor(self):
        print self._haircolor

c = Child()
c.print_haircolor()

Why does Mother.__init__(self) work fine (it outputs Brown ), but super(Mother, self).__init__(self) give the error

Traceback (most recent call last):
  File "test2.py", line 13, in <module>
    c = Child()
  File "test2.py", line 8, in __init__
    super(Mother, self).__init__(self)
TypeError: object.__init__() takes no parameters

I've seen this , this , this and this , but it doesn't answer the question.

Answer 1

You have two related issues.

First, as the error states, object.__init__() takes no arguments, but by running super(Mother, self).__init__(self) , you're trying to pass in an instance of Child to the constructor of object . Just run super(Mother, self).__init__() .

But second and more importantly, you're not using super correctly. If you want to run the constructor of the Mother class in Child , you need to pass in the subclass Child , not the superclass Mother . Thus, what you want is super(Child, self).__init__(self) .

When these fixes are added to your code, it runs as expected:

class Mother(object):
    def __init__(self):
        self.haircolor = "Brown"

class Child(Mother):
    def __init__(self): 
        super(Child, self).__init__()

    def print_haircolor(self):
        print self.haircolor

c = Child()
c.print_haircolor() # output: brown