Python Multiple Inheritance

Multiple inheritance is a foundational concept in object-oriented programming (OOP) where a class can inherit methods and attributes from more than one parent class. Python supports this, allowing a subclass to combine functionality from multiple base classes.

This promotes flexibility and code reuse. However, it also raises the risk of method name conflicts. Python resolves such issues using its Method Resolution Order (MRO).

Syntax

class ParentA:
  # Methods and attributes of ParentA

class ParentB:
  # Methods and attributes of ParentB

class Child(ParentA, ParentB):
  # Inherits from both ParentA and ParentB

Here:

• ParentA, ParentB: Two distinct base classes.
• Child: The derived class that inherits from both.

Python determines which method to use using the order declared (left to right).

Example

In this example, the Duck class inherits from both Flyer and Swimmer, but due to Python’s MRO, the method from Flyer takes priority:

class Flyer:
  def ability(self):
    return "Can fly"

class Swimmer:
  def ability(self):
    return "Can swim"

class Duck(Flyer, Swimmer):
  pass

d = Duck()
print(d.ability())

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The output of this code is:

Can fly

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Codebyte Example

In this codebyte example, the Tablet class inherits input methods from both Keyboard and Touchscreen, but the method from Keyboard is used due to its position in the inheritance list:

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A visual overview of multiple inheritance:

+-------------+     +---------------+
|  Keyboard   |     |  Touchscreen  |
|-------------|     |---------------|
| input_method|     | input_method  |
+------+------+     +-------+-------+
       \                  /
        \                /
         ▼              ▼
          +--------------------+
          |      Tablet        |
          |--------------------|
          |    description()   |
          +--------------------+