CODEWITHSUNDEEP
pythonpython-2.7oopinheritancemultiple-inheritance
Swastik Udupa
Swastik Udupa

Reputation: 316

ChildClass object has no attribute bar

class Foo(Baz, Qux):
    def __init__(self, bar, *args, **kwargs):
        super(Foo, self).__init__(bar=bar, *args, **kwargs)

class Baz:   
    def __init__(self, bar, *args, **kwargs):
        self.bar = bar

This is the structure of my classes with the Foo class inheriting the Baz class. However when I try running the code, I get the following error Foo object has no attribute bar

From what I understand, the super(childclass, self).__init__(parent, attributes) should initialize the parent class as well. Why should bar be present in the child class too?

I followed the following stack answers to implement this: Calling parent class __init__ with multiple inheritance, what's the right way?

EDIT

class Qux:   
    def __init__(self, xyz, *args, **kwargs):
        self.xyz = xyz
    
    def print_barqux(self):
        print(self.xyz)
        
class Baz:   
    def __init__(self, bar, *args, **kwargs):
        self.bar = bar
        
class Foo(Baz, Qux):
    def __init__(self, bar, xyz, *args, **kwargs):
        super(Foo, self).__init__(bar=bar, xyz=xyz)

    def printbar(self):
        super(Foo, self).print_barqux()
        
        
foo = Foo(bar="abcd", xyz="abcdef")
print(foo.printbar())

Output:

Traceback (most recent call last):
  File "./prog.py", line 21, in <module>
  File "./prog.py", line 17, in printbar
  File "./prog.py", line 6, in print_barqux
AttributeError: 'Foo' object has no attribute 'xyz'

Adding the error stacktrace with code

Upvotes: 1

Views: 154

Answers (1)

Daniel
Daniel

Reputation: 42778

Every class has to call super.__init__:

class Qux:   
    def __init__(self, xyz, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.xyz = xyz
    
    def print_barqux(self):
        print(self.xyz)
        
class Baz:   
    def __init__(self, bar, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.bar = bar
        
class Foo(Baz, Qux):
    def __init__(self, bar, xyz, *args, **kwargs):
        super().__init__(bar=bar, xyz=xyz)

    def printbar(self):
        super().print_barqux()
        
        
foo = Foo(bar="abcd", xyz="abcdef")
print(foo.printbar())

Upvotes: 3

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