Python Forum
Why Can't I call base class function for my derived class object?
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Why Can't I call base class function for my derived class object?
#1
Hi experts!
Any idea if I am making an error in my code as I am not able to understand Why Can't I call the the base class function for my derived class object?
class My_base_class():
    def __init__(self):
        print("This is __init__function of Base Class")
    def base_class_func1(self):
        print("my base class function")
    def base_class_func2(self):
        print("my base class function # 2")     
       
class My_derived_class():
    def __init__(self):
        My_base_class.__init__(self)
        print("I am inside my __init__function of my Drived Class")
    def base_class_func1(self):
        print("my base class function")    
    def derived_class_func1(self):
        print("I am inside my derived class function 01")
        
my_inherit=My_derived_class()
my_inherit.base_class_func2()# I get error while I call function of base class.
Error:'My_derived_class' object has no attribute 'base_class_func2'
Reply
#2
class My_base_class():
    def __init__(self):
        print("This is __init__function of Base Class")
    def base_class_func1(self):
        print("my base class function")
    def base_class_func2(self):
        print("my base class function # 2")     
        
class My_derived_class(My_base_class):
    def __init__(self):
        My_base_class.__init__(self)
        print("I am inside my __init__function of my Drived Class")
    def base_class_func1(self):
        print("my base class function")    
    def derived_class_func1(self):
        print("I am inside my derived class function 01")
         
my_inherit=My_derived_class()
my_inherit.base_class_func2()# I get error while I call function of base class.
Reply
#3
To fix and update some stuff Wink
It not a function when it has self,then is a method that belong to the class.
Start using super(),and look at PEP-8
class BaseClass:
    def __init__(self):
        print("This is __init__method of Base Class")

    def base_method1(self):
        print("Only work in Base class <overridden> in DerivedClass")

    def base_method2(self):
        print("my base class method # 2")

class DerivedClass(BaseClass):
    def __init__(self):
        super().__init__()
        print("I am inside my __init__method of my Drived Class")

    def base_method1(self):
        print("DerivedClass class method")

    def derived_method1(self):
        print("I am inside my derived class method 01")

my_inherit = DerivedClass()
my_inherit.base_method2() 
Output:
This is __init__method of Base Class I am inside my __init__method of my Drived Class my base class method # 2

To take a little about Method overriding,which can be confusing.
See my comment Only work in Base class <overridden> in DerivedClass
So using DerivedClass will base_method1 in BaseClass has no functions as is overridden.

To show a example where both method has same name,but we as add information about date.
This can be called pre-filtering and post-filtering if doing method overriding.
from datetime import datetime

class BaseClass():
    def __init__(self):
        print("This is __init__method of Base Class")

    def base_method1(self, message):
        print(f'base_method1 say {message}')

    def base_method2(self):
        print("My base class method # 2")

class DerivedClass(BaseClass):
    def __init__(self):
        super().__init__()
        print("I am inside my __init__method of my Drived Class")

    def base_method1(self, message):
        date_info = f'at time {datetime.now():%B %d, %Y}'
        super().base_method1(f'{message} {date_info}')

    def derived_method1(self):
        print("I am inside my derived class method 01")

my_inherit = DerivedClass()
my_inherit.base_method2()
Use:
>>> obj = BaseClass()
This is __init__method of Base Class

>>> obj.base_method1('hello')
base_method1 say hello
Now using same base_method1 from DerivedClass,it will add info about date.
>>> obj = DerivedClass()
This is __init__method of Base Class
I am inside my __init__method of my Drived Class

>>> obj.base_method1('hello')
base_method1 say hello at time February 13, 2019
Reply


Possibly Related Threads…
Thread Author Replies Views Last Post
  class and runtime akbarza 4 212 Mar-16-2024, 01:32 PM
Last Post: deanhystad
  Operation result class SirDonkey 6 393 Feb-25-2024, 10:53 AM
Last Post: Gribouillis
  The function of double underscore back and front in a class function name? Pedroski55 9 527 Feb-19-2024, 03:51 PM
Last Post: deanhystad
  super() and order of running method in class inheritance akbarza 7 580 Feb-04-2024, 09:35 AM
Last Post: Gribouillis
  Class test : good way to split methods into several files paul18fr 4 380 Jan-30-2024, 11:46 AM
Last Post: Pedroski55
  Good class design - with a Snake game as an example bear 1 1,703 Jan-24-2024, 08:36 AM
Last Post: annakenna
  question about __repr__ in a class akbarza 4 505 Jan-12-2024, 11:22 AM
Last Post: DeaD_EyE
  error in class: TypeError: 'str' object is not callable akbarza 2 418 Dec-30-2023, 04:35 PM
Last Post: deanhystad
  super() in class akbarza 1 386 Dec-19-2023, 12:55 PM
Last Post: menator01
  error occuring in definition a class akbarza 3 600 Nov-26-2023, 09:28 AM
Last Post: Yoriz

Forum Jump:

User Panel Messages

Announcements
Announcement #1 8/1/2020
Announcement #2 8/2/2020
Announcement #3 8/6/2020