CODEWITHSUNDEEP
pythonclassinheritance
user3500869
user3500869

Reputation: 172

What does inheritance actually do in Python?

I'm struggling with how I should interpret class inheritance. What does it actually do? As far as I know, it allows your class to:

Does this go both ways? If something is inherited, will it be able to read his inheriter as well?

Please give your answer in as much layman's terms as possible. I'm not an native Englisch speaker and I've never had proper programming education. Give me an explenation, not a definiton :]

Upvotes: 2

Views: 113

Answers (2)

Mihai Zamfir
Mihai Zamfir

Reputation: 2166

Let's say you have a class called Animal. In this class you have a method called walk, that prints "Animal is walking"

Now you have 2 other classes:

1. Class Bird that is inherited from Animal. You can now add an additional method to it: fly. This will print that a bird can fly.

2. Class Monkey that is inherited from Animal as well. You can now add an additional method to it: climb. This will print that a monkey can climb trees.

Both Monkey and Bird derive from Animal, so they can walk, they have a same functionality/feature. But both have a distinct feature as well: birds can fly and monkeys can climb trees. So it takes sense, right?

The reverse is false, because not every Animal can fly or can climb trees.

EDIT: I exaplined it to you in terms of methods. But this can apply to variables as well. The Animal class can have a weight field. Which is accessible from both inherited classes: Monkey and Bird.

But Monkey can also have a field called max_power and Bird can have a class variable called max_fly_altitude. This fields are unique for these certain types of animal and NOT for the generic Animal. Which can also be a crocodile. And a crocodile can't fly to have a max_fly_altitude attribute.

Upvotes: 2

sshashank124
sshashank124

Reputation: 32197

Inheritance does not work both ways. Here is what I mean:

If you have a class called Father and another class called Son which inherits from father as class Son(Father), then Son can use all the methods from the Father class but the Father cannot use the methods from the Son class.

Examples

class A:
    def get_val(self):
        return 5

class B(A):
    def num(self):
        return 3

>>> a = A()
>>> b = B()
>>> a.get_val()
5
>>> b.num()
3
>>> b.get_val()
5
>>> a.num()
Attribute Error: A instance has no attribute 'num'

Analogy

class Musician:
    def get_type(self):
        return 'musician'

class Pianist(Musician):
    def get_prof(self):
        return 'pianist'

>>> m = Musician()
>>> p = Pianist()
>>> m.get_type()
'musician'
>>> p.get_type()
'musician'
>>> p.get_prof()
'pianist'
>>> m.get_prof()
Attribute Error: Musician instance has no attribute 'get_prof'

Upvotes: 1

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