mirror of
https://github.com/Brandon-Rozek/website.git
synced 2024-11-29 20:57:09 -05:00
46 lines
1.3 KiB
Markdown
46 lines
1.3 KiB
Markdown
---
|
|
title: "Quick Python: Abstract Classes"
|
|
date: 2020-01-26T18:40:03-05:00
|
|
draft: false
|
|
tags: [ "python" ]
|
|
---
|
|
|
|
You can create an abstract class in Python by inheriting Abstract Base Class (`ABC`) and declaring relevant methods abstract.
|
|
|
|
First import the following from the standard library,
|
|
|
|
```python
|
|
from abc import ABC, abstractmethod
|
|
```
|
|
|
|
Then create an abstract class, making sure to add the decorator `@abstractmethod` to the constructor. This prevents the user from instantiating the class.
|
|
|
|
```python
|
|
class Animal(ABC):
|
|
@abstractmethod
|
|
def __init__(self, name):
|
|
self.name = name
|
|
@abstractmethod
|
|
def is_bipedal(self):
|
|
pass
|
|
def speak(self):
|
|
return "Hello my name is " + self.name + " and I am a " + type(self).__name__
|
|
```
|
|
|
|
In the example above:
|
|
|
|
- A constructor is made, however, the class Animal cannot be instantiated. Do note that child classes can call the constructor.
|
|
- `is_bipedal` is an abstract method that needs to be defined in child classes. `pass` indicates that it is not implemented.
|
|
- `speak` is a normal method that will be inherited by child classes.
|
|
|
|
Now let's look at a class that inherits `Animal`.
|
|
|
|
```python
|
|
class Dog(Animal):
|
|
def __init__(self, name, owner):
|
|
super().__init__(name) # Calls Animal constructor
|
|
self.owner = owner
|
|
def is_bipedal(self):
|
|
return False
|
|
```
|
|
|