45 lines
1.2 KiB
Markdown
45 lines
1.2 KiB
Markdown
|
In [TypeScript](./Classes_in_TypeScript.md) we can use interfaces to implement
|
||
|
|
classes and use `abstract` to create abstract methods:
|
||
|
|
|
||
|
|
```ts
|
||
|
|
interface Person {
|
||
|
|
firstName: string;
|
||
|
|
calculateAge(): number;
|
||
|
|
}
|
||
|
|
|
||
|
|
class Programmer implements Person {}
|
||
|
|
// Must include the property firstName and the method calculateAge
|
||
|
|
```
|
||
|
|
|
||
|
|
```ts
|
||
|
|
abstract class Person {
|
||
|
|
abstract calculateAge(): number;
|
||
|
|
}
|
||
|
|
|
||
|
|
class Child extends Person {}
|
||
|
|
// Must concretize the abstract calculateAge method from the parent class
|
||
|
|
```
|
||
|
|
|
||
|
|
The same --or very similar-- functionality can be achieved in Python by
|
||
|
|
importing the `abc` module ("Abstract Base Class").
|
||
|
|
|
||
|
|
```py
|
||
|
|
from abc import ABC, abstractmethod
|
||
|
|
|
||
|
|
class Person(ABC):
|
||
|
|
@abstractmethod
|
||
|
|
def calculate_age(self):
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
class Child(Person):
|
||
|
|
def calculate_age(self):
|
||
|
|
# Must concretize the abstract method in Person
|
||
|
|
```
|
||
|
|
|
||
|
|
> Only use `@abstractmethod` if the method _must_ exist on the child and _must_
|
||
|
|
> be defined in the child (not the parent). If you just want to redefine a
|
||
|
|
> parent method, you can use
|
||
|
|
> [normal inheritance](./Class_inheritance_in_Python.md). Python will interpret
|
||
|
|
> the methods upwards from the child, before getting to the parent.
|