13.7. OOP Inheritance Patterns¶

13.7.1. Rationale¶

single inheritance¶: One class inherits from one other class. Has one parent.
multilevel inheritance¶: One class inherits from other class, and yet another class inherits from it. This creates hierarchical structure.
multiple inheritance¶
mixin classes¶: One class derives from several other classes at once.

13.7.2. No Inheritance¶

>>> class Parent:
...     pass
>>>
>>>
>>> class Child:
...     pass

13.7.3. Single Inheritance¶

>>> class Parent:
...     pass
>>>
>>>
>>> class Child(Parent):
...     pass

13.7.4. Multilevel Inheritance¶

>>> class Person:
...     pass
>>>
>>>
>>> class Parent(Person):
...     pass
>>>
>>>
>>> class Child(Parent):
...     pass

13.7.5. Multiple Inheritance¶

>>> class Mother:
...     pass
>>>
>>>
>>> class Father:
...     pass
>>>
>>>
>>> class Child(Mother, Father):
...     pass

13.7.6. Assignments¶

Code 13.12. Solution¶

"""
* Assignment: OOP InheritancePatterns Multilevel
* Complexity: easy
* Lines of code: 8 lines
* Time: 3 min

English:
    1. Create class `MarsMission` from classes `Habitat`, `Rocket`, `Astronaut`
    2. Use multilevel inheritance
    3. Assignment demonstrates syntax, so do not add any attributes and methods
    4. Run doctests - all must succeed

Polish:
    1. Stwórz klasę `MarsMission` z klas `Habitat`, `Rocket`, `Astronaut`
    2. Użyj wielopoziomowego dziedziczenia
    3. Zadanie demonstruje składnię, nie dodawaj żadnych atrybutów i metod
    4. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from inspect import isclass

    >>> assert isclass(Habitat)
    >>> assert isclass(Astronaut)
    >>> assert isclass(Rocket)
    >>> assert isclass(MarsMission)
    >>> assert issubclass(MarsMission, Habitat)
    >>> assert issubclass(MarsMission, Astronaut)
    >>> assert issubclass(MarsMission, Rocket)

    >>> assert len(Habitat.__subclasses__()) == 1
    >>> assert len(Astronaut.__subclasses__()) == 1
    >>> assert len(Rocket.__subclasses__()) == 1
    >>> assert len(MarsMission.__subclasses__()) == 0
"""

Code 13.13. Solution¶

"""
* Assignment: OOP InheritancePatterns Mixin
* Complexity: easy
* Lines of code: 8 lines
* Time: 3 min

English:
    1. Create class `MarsMission` from classes `Habitat`, `Rocket`, `Astronaut`
    2. Use mixins classes
    3. You can modify given classes
    4. Assignment demonstrates syntax, so do not add any attributes and methods
    5. Run doctests - all must succeed

Polish:
    1. Stwórz klasę `MarsMission` z klas `Habitat`, `Rocket`, `Astronaut`
    2. Użyj klas domieszkowych (mixin)
    3. Możesz modyfikować dane klasy
    4. Zadanie demonstruje składnię, nie dodawaj żadnych atrybutów i metod
    5. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from inspect import isclass

    >>> assert isclass(Habitat)
    >>> assert isclass(Astronaut)
    >>> assert isclass(Rocket)
    >>> assert isclass(MarsMission)
    >>> assert issubclass(MarsMission, Habitat)
    >>> assert issubclass(MarsMission, Astronaut)
    >>> assert issubclass(MarsMission, Rocket)

    >>> assert len(Habitat.__subclasses__()) == 1
    >>> assert len(Astronaut.__subclasses__()) == 1
    >>> assert len(Rocket.__subclasses__()) == 1
    >>> assert len(MarsMission.__subclasses__()) == 0
"""