Python
docs.python.org › 3 › library › abc.html
abc — Abstract Base Classes
This module provides the infrastructure for defining abstract base classes (ABCs) in Python, as outlined in PEP 3119; see the PEP for why this was added to Python.
Python Course
python-course.eu › oop › the-abc-of-abstract-base-classes.php
20. The 'ABC' of Abstract Base Classes | OOP | python-course.eu
from abc import ABC, abstractmethod class AbstractClassExample(ABC): def __init__(self, value): self.value = value super().__init__() @abstractmethod def do_something(self): pass
abstract class, how to create it properly?
create an abstract base class with two int attributes That's not really possible in python. An abstract class must have at least one method decorated with @abc.abstractmethod. You can't make an abstract class with just 2 attributes. You should ask your professor to clarify what they want you to do. More on reddit.com
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March 24, 2024Understanding abc.ABC
If I have class A and then I derive subclass B from it wouldn't issubclass(B,A) still be true? Usually, yes, unless you do something weird with metaclasses maybe. I do not understand what abstract classes give you. You can think of them as some kind of "contracts"; any class inheriting from them implicitly makes a promise to support the interface defined by the abstract base class. It's not nearly as binding or robust as something like Rust's trait system, but it can still come in handy sometimes. For example, os.PathLike is an abstract base class that defines a common interface all path-like objects, such as pathlib.Path, must fulfill to be compatible with most standard library functions expecting filepaths as arguments. The subclasses can add more functionality on top of the required methods, but they are forced to at least have the ones set by the abstract base class. In other words, you can always count on those being available no matter what kind of subclass you're getting. More on reddit.com
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June 20, 2023How define constructor implementation for an Abstract Class in Python? - Stack Overflow
The arguments passed to __new__ ... to __init__ after __new__ returns an instance. You don't want to forward them to object.__new__, because it doesn't accept them. 2017-06-28T11:30:18.62Z+00:00 ... Oh, nevermind, this works in python 2. Weird. Still, there's no reason to forward the parameters, is there? 2017-06-28T11:34:20.177Z+00:00 ... You should define the methods as abstract as well with the @abc.abstractmethod ... More on stackoverflow.com
Enforcing __init__ signature when implementing it as an abstractmethod - Typing - Discussions on Python.org
Hello. I noticed that Pyright doesn’t check the signatures of abstractmethod implementations when the abstractmethod is __init__(). Here’s an example: from abc import ABC, abstractmethod class AbstractA(ABC): @abstractmethod def __init__(self, x: int, y: int): pass @abstractmethod def ... More on discuss.python.org
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December 29, 2024Videos
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W3Schools
w3schools.com › python › ref_module_abc.asp
Python abc Module
Python Examples Python Compiler ... Python Certificate Python Training · ❮ Standard Library Modules · Define an abstract base class and implement it: from abc import ABC, abstractmethod class Shape(ABC): @abstractmethod def ...
Earthly
earthly.dev › blog › abstract-base-classes-python
Abstract Base Classes in Python - Earthly Blog
July 19, 2023 - Let’s consider the Shape ABC we defined in the interfaces section, we have different shapes such as circles, rectangles, and triangles. Each shape has an area and a perimeter, so any class that inherits from Shape must implement both the area and perimeter methods. For example, we can define a Square concrete class that will inherit from Shape and provide implementations for both methods. # shape.py class Square(Shape): def __init__(self, side_length): self.side_length = side_length def area(self): return self.side_length ** 2 def perimeter(self): return 4 * self.side_length
Geek Python
geekpython.in › abc-in-python
Python's ABC: Understanding the Basics of Abstract Base Classes
October 29, 2023 - Python doesn’t allow creating objects for abstract classes because there is no actual implementation to invoke rather they require subclasses for implementation. ... We got the error stating that we cannot instantiate the abstract class Details with abstract methods called getname and getrole. Just as the abc module allows us to define abstract methods using the @abstractmethod decorator, it also allows us to define abstract properties using the @abstractproperty decorator.
DEV Community
dev.to › sachingeek › getting-started-with-pythons-abc-4b95
Getting Started With Python's ABC - DEV Community
April 6, 2023 - Python is not a fully object-oriented programming language but it supports the features like abstract classes and abstraction. We cannot create abstract classes directly in Python, so Python provides a module called abc that provides the infrastructure for defining the base of Abstract Base Classes(ABC).
DataCamp
datacamp.com › tutorial › python-abstract-classes
Python Abstract Classes: A Comprehensive Guide with Examples | DataCamp
January 22, 2025 - The ABC class is a built-in Python feature that serves as a fundamental basis for developing abstract classes. You must inherit from ABC to define an abstract class. The class is abstract and cannot be instantiated directly, as indicated by this inheritance.
DEV Community
dev.to › sarahs › abstract-classes-in-python-55mj
Abstract Classes in Python - DEV Community
December 20, 2023 - ... Title:, a space, and then the current instance's title. Author:, a space, and then the current instance's author. Price:, a space, and then the current instance's price. ... from abc import ABCMeta, abstractmethod class Book(object, ...
Reddit
reddit.com › r/learnpython › abstract class, how to create it properly?
r/learnpython on Reddit: abstract class, how to create it properly?
March 24, 2024 -
I thought I understood what abstract class means but my professor just commented that it wasn't a abstract class. What I did is essentially this:
first instruction: create an abstract base class with two int attributes then derived another class called Hero with a string attribute which stores the title "hero"
from abc import ABC
class Person(ABC):
def __init__(self, height, speed):
self.height = height
self.speed = speed
def walk(self):
//walk method
from person import Person
class Hero(Person):
def __init__(self, height, speed):
super().__init__(height, speed)
self.person_title = "Hero"
was this the right way to do it?
Top answer 1 of 4
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create an abstract base class with two int attributes That's not really possible in python. An abstract class must have at least one method decorated with @abc.abstractmethod. You can't make an abstract class with just 2 attributes. You should ask your professor to clarify what they want you to do.
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It depends what your professor thinks "abstract class" means. Originally, abstract classes couldn't have any attributes, so that's out of the window. Others might say abstract classes are just classes that can't be instantiated directly, if that's your professor definition then yours work. You might also say that anything that inherits from ABC is abstract In reality, the example doesn't make much sense because the whole point of abstract classes is to enforce some kind of structure to subtypes and the example doesn't do that, Person could be a normal class. For example from abc import ABC, abstractmethod class Person(ABC): @abstractmethod def speak(): ... from person import Person class Hero(Person): def __init__(self): self.person_title = "Hero" def speak(self): print("foo") Now this makes sense because you're enforcing that Hero implements a speak method, it's impossible to forget to do that
Machine Learning Plus
machinelearningplus.com › blog › python abcs- the complete guide to abstract base classes
Python ABCs- The Complete Guide to Abstract Base Classes
July 15, 2025 - pythonCopy · # Simple abstract base class for documents class Document(ABC): def __init__(self, title): self.title = title @abstractmethod def save(self): pass @abstractmethod def get_extension(self): pass · The @abstractmethod decorator marks methods that must be implemented by subclasses.
Medium
medium.com › @mhesty71 › what-i-wish-i-knew-about-init-self-super-and-abstract-classes-7103c8b91128
What I Wish I Knew About __init__, self, super(), and Abstract Classes | by maria siagian | Medium
December 17, 2024 - When I started learning Object-Oriented Programming (OOP) in Python, these concepts — __init__, self, super(), and Abstract Base Classes (ABC)—felt like a puzzle. What exactly does __init__ do? What does self actually represent? What’s the point of super()?
Reddit
reddit.com › r/learnpython › understanding abc.abc
r/learnpython on Reddit: Understanding abc.ABC
June 20, 2023 -
I am being asked to maintain code that subclasses from abc.ABC. I have read the python documentation, the associated PEP, and even visited pymotw. I do not understand what abstract classes give you.
If I have class A and then I derive subclass B from it wouldn't issubclass(B,A) still be true?
Top answer 1 of 4
4
If I have class A and then I derive subclass B from it wouldn't issubclass(B,A) still be true? Usually, yes, unless you do something weird with metaclasses maybe. I do not understand what abstract classes give you. You can think of them as some kind of "contracts"; any class inheriting from them implicitly makes a promise to support the interface defined by the abstract base class. It's not nearly as binding or robust as something like Rust's trait system, but it can still come in handy sometimes. For example, os.PathLike is an abstract base class that defines a common interface all path-like objects, such as pathlib.Path, must fulfill to be compatible with most standard library functions expecting filepaths as arguments. The subclasses can add more functionality on top of the required methods, but they are forced to at least have the ones set by the abstract base class. In other words, you can always count on those being available no matter what kind of subclass you're getting.
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Abstract base classes are just classes that aren't meant to be instantiated. It is like a wireframe for shared methods / attributes, without the ABC itself being a legitimate object type. It works the same as regular subclassing in most ways. ABCs usually have the shared methods defined so that if you make a subclass of it and it doesn't implement something the interface was expected to it will throw an error. class PersonNormal: def __init__(self, name: str): self.name = name def say_hi(self): print(f"Hi, I'm {self.name}") class PersonABC(ABC): def __init__(self, name): ... @abstractmethod def say_hi(self): ... class Student(Person): def __init__(self, name: str): super().__init__(name) class Teacher(Person) def __init__(self, name: str): super().__init__(name) def say_hi(self): print(f"Good morning, I'm Mr. {self.name}") # inheriting from PersonNormal A = Person('John') B = Student('Peter') C = Teacher('Tom') A.say_hi() # calls Person.say_hi normally B.say_hi() # calls Person.say_hi since it wasn't overwritten C.say_hi() # calls Teacher.say_hi # inheriting from PersonABC A = Person('John') # TypeError can't instantiate abstract class Person... B = Student('Peter') # TypeError since you didn't overwrite the method C = Teacher('Tom') # works as expected
Top answer 1 of 6
101
Making the __init__ an abstract method:
from abc import ABCMeta, abstractmethod
class A(object):
__metaclass__ = ABCMeta
@abstractmethod
def __init__(self, n):
self.n = n
if __name__ == '__main__':
a = A(3)
helps:
TypeError: Can't instantiate abstract class A with abstract methods __init__
Python 3 version:
from abc import ABCMeta, abstractmethod
class A(object, metaclass=ABCMeta):
@abstractmethod
def __init__(self, n):
self.n = n
if __name__ == '__main__':
a = A(3)
Works as well:
TypeError: Can't instantiate abstract class A with abstract methods __init__
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A not so elegant solution can be this:
class A(object):
def __init__(self, n):
if self.__class__ == A:
raise Exception('I am abstract!')
self.n = n
Usage
class B(A):
pass
a = A(1) # Will throw exception
b = B(1) # Works fine as expected.
CodeFatherTech
codefather.tech › home › blog › create an abstract class in python: a step-by-step guide
Create an Abstract Class in Python: A Step-By-Step Guide
December 8, 2024 - Have you enjoyed this tutorial? We went through quite a lot! We have started by explaining the concept of abstract classes that represent a common interface to create classes that follow well-defined criteria. The name of the Python module we have used in all the examples is ABC (Abstract Base Classes).
CodeConverter
codeconverter.com › articles › python-abstract-class-example
Python Abstract Classes: ABC Module Tutorial | CodeConverter Blog
February 12, 2026 - from abc import ABC, abstractmethod class AbstractClassExample(ABC): @property @abstractmethod def some_property(self): pass class ConcreteClass(AbstractClassExample): def __init__(self): self._some_property = "Hello, world!" @property def some_property(self): return self._some_property @some_property.setter def some_property(self, value): self._some_property = value obj = ConcreteClass() print(obj.some_property) # Output: Hello, world!
Upgrad
upgrad.com › home › tutorials › software & tech › abstract class in python
Abstract Class in Python | With Example and Interface Comparison
June 1, 2025 - In Python, abstract base classes (ABCs) can also contain concrete methods—methods that are completely implemented in the abstract class itself. The presence of concrete methods in an abstract class allows for a blend of enforced structure and reusable code. ... class Animal(ABC): @abstractmethod def sound(self): pass # Concrete method def describe(self): return "This is an animal." # Create a subclass of Animal class Dog(Animal): def __init__(self, name): self._name = name # Implement the abstract method def sound(self): return "Bark" # Create another subclass of Animal class Cat(Animal): de
Python.org
discuss.python.org › typing
Enforcing __init__ signature when implementing it as an abstractmethod - Typing - Discussions on Python.org
December 29, 2024 - Hello. I noticed that Pyright doesn’t check the signatures of abstractmethod implementations when the abstractmethod is __init__(). Here’s an example: from abc import ABC, abstractmethod class AbstractA(ABC): @abstractmethod def __init__(self, x: int, y: int): pass @abstractmethod def do_something(self, z: int, u: int): pass class RealA(AbstractA): def __init__(self, x: int): ## No static type checker error self.x = x def do_something...
GeeksforGeeks
geeksforgeeks.org › abstract-base-class-abc-in-python
Abstract Base Class (abc) in Python - GeeksforGeeks
August 29, 2020 - Python has a module called abc (abstract base class) that offers the necessary tools for crafting an abstract base class. First and foremost, you should understand the ABCMeta metaclass provided by the abstract base class.
GeeksforGeeks
geeksforgeeks.org › python › abstract-classes-in-python
Abstract Classes in Python - GeeksforGeeks
from abc import ABC, abstractmethod class Animal(ABC): @abstractmethod def make_sound(self): pass # animal = Animal() # TypeError: Can't instantiate abstract class Animal with abstract methods make_sound
Published September 3, 2025
Python Tutorial
pythontutorial.net › home › python oop › python abstract classes
Python Abstract Class
March 31, 2025 - from abc import ABC, abstractmethod class AbstractClassName(ABC): @abstractmethod def abstract_method_name(self): pass Code language: Python (python)