CODEWITHSUNDEEP
pythonclassinheritance
NullException
NullException

Reputation: 4510

Python subclass does not display parent class attributes

I am using python 2.6

class Father(object):
    def __init__(self, *args, **kwargs):
        self.is_rich = 'yes'
        self.single  = 'yes'

class Son(Father):
    def __init__(self, *args, **kwargs):
        self.has_job = 'yes'

son = Son()
print dir(son)  --> Does not display Father class attributes is_rich & single?

Why?

Upvotes: 1

Views: 584

Answers (3)

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 251116

You need to call base class's __init__, as python only invokes the first __init__ method found in the class hierarchy the __init__ in Father is never invoked. You can do that using super or using Father.__init__ as shown in @mgilson's answer.

class Son(Father):
    def __init__(self, *args, **kwargs):
        super(Son, self).__init__(*args, **kwargs)
        self.has_job = 'yes'

Demo:

>>> s = Son()
>>> s.is_rich
'yes'
>>> s.single
'yes'
>>> s.has_job
'yes'

Upvotes: 2

Jim Dennis
Jim Dennis

Reputation: 17510

Looks like you didn't have your child chain the initialization up towards its parent.

Perhaps reading this will help: Why aren't Python's superclass __init__ methods automatically invoked?

Upvotes: 2

mgilson
mgilson

Reputation: 310117

You didn't call Father.__init__. You need to do so explicitly or use super1,2:

class Son(Father):
    def __init__(self, *args, **kwargs):
        Father.__init__(self, *args, **kwargs)
        self.has_job = 'yes'

1super considered Super!
2super considered harmful

Upvotes: 3

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