Python Forum

I am pasting my code below:-

class A:
    def __init__(self,i=100): 
      self.i=100
   

class B(A): 
   def __init__(self,j=0): 
      self.j=j 


b=B()
print(b.j)
print(b.i)

I have 2 class A and B . B is inheriting class A so according to the concept of inheritance base class acquires property of parent class so Instance variable i must be accessible to class B . But it is giving me an error that :

Error:
Traceback (most recent call last):
  File "D:/PYTHON/jljl.py", line 16, in <module>
    print(b.i)
AttributeError: 'B' object has no attribute 'i'

Why this is giving error.

you forgot to initialize the instance of A in B

class A:
    def __init__(self,i=100): 
      self.i=100
    
 
class B(A): 
   def __init__(self,j=0):
       A.__init__(self)
       self.j=j 


b=B()
print(b.j)
print(b.i)

Not that relevant when your class inherits from single class, but in any case better to use super()

class A:
    def __init__(self, i=100): 
        self.i=100
    
 
class B(A): 
   def __init__(self, j=0):
        super().__init__()
        self.j=j 
 
 
b=B()
print(b.j)
print(b.i)

some external resources
https://realpython.com/python-super/
https://stackoverflow.com/questions/2228...-in-python

You need to call __init__ from A in B:

class B(A): 
   def __init__(self, i, j=0): 
      A.__init__(self, i)
      self.j=j