how to use mixin class to provide method to multiple class in python

Question

I am trying to understand how to use mixins in python. I want to make Bird, Dog and Bat class to have the eat method from PetMixIn class but also can be self instance. How should I do it?

class Pet(object):
    def __init__(self, food):
        self.food = food
    def eat(self):
        print(f'Eatting...{self.food}')

class PetMixIn(object):
    def eat(self):
        print('Eatting...')

class Animal(object):
    def __init__(self, life):
        self.liferange = life

class Bird(Animal):
    def __init__(self, life, flyable):
        super.__init__(lift)
        self.flyable = flyable
    #bird attribution ...

class Dog(Animal):
    def __init__(self, life, name):
        super.__init__(lift)
        self.name = name
    #dog attribution ...

class Bat(Animal):
    def __init__(self, life, size):
        super.__init__(lift)
        self.size = size
    #bat attribution ...
bat = Bat(40, '1')
dog = Dog(10, 'tom')
bird = Bird(3, True)

Possible duplicate of [What is a mixin, and why are they useful?](https://stackoverflow.com/questions/533631/what-is-a-mixin-and-why-are-they-useful) — ScottMcC, Apr 05 '18 at 14:01
You aren't even using the mixin. Have you tried inheriting from it? — Aran-Fey, Apr 05 '18 at 14:01
This case doesn't need a mixin. Move the `eat` method into `Animal`. — quamrana, Apr 05 '18 at 14:03

djangoliv · Answer 1 · 2018-04-05T16:05:40.363

2

Here a small example (python3)

class PetMixIn:
    xxx = 2
    def eat(self):
        print('Eatting...')

class Animal:
    def __init__(self, life):
        self.liferange = life

class Bat(Animal, PetMixIn):
    def __init__(self, life, size):
        super().__init__(life)
        self.size = size
    #bat attribution ...

bat = Bat(40, '1')
bat.eat()
print(bat.xxx)

edited Apr 05 '18 at 16:05

answered Apr 05 '18 at 14:09

djangoliv

1,698
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what if I have some attribution in PetMixIn need to use? like *self.xxx*? – jacobcan118 Apr 05 '18 at 15:45
not sure to understand. You want an __init__ in your mixin ? – djangoliv Apr 05 '18 at 16:07
The `PetMixIn` class has the method `def eat(self):`. And there it is: `self` in the method signature. Any method you define on the mixin can use `self` any way an `Animal` would, even though there is no inheritance connection. Python is a dynamic language after all. – quamrana Apr 06 '18 at 07:44

how to use mixin class to provide method to multiple class in python

1 Answers1