Hackerrank Object-Oriented Programming Basics 2

Question 1

Which method is automatically called when an object is created from a class?

Accepted Answer

__init__

Answer

__init__ is the initializer method called automatically after object creation to set up instance attributes.

Question 2

What does the 'self' parameter in an instance method refer to?

Accepted Answer

The current instance of the class

Answer

'self' refers to the current instance of the class, allowing access to instance attributes and methods.

Question 3

What will the following code output?
class Dog:
    def __init__(self, name):
        self.name = name
d = Dog('Rex')
print(d.name)

Accepted Answer

Rex

Answer

d.name accesses the instance attribute 'name' set during __init__, which was given the value 'Rex'.

Question 4

Which keyword is used to inherit from a parent class in Python?

Accepted Answer

The parent class is passed in parentheses

Answer

Python uses class ChildClass(ParentClass): syntax — the parent class name is placed in parentheses after the child class name.

Question 5

What is a class attribute vs an instance attribute?

Accepted Answer

Class attributes are shared by all instances; instance attributes are unique per object

Answer

Class attributes are defined at the class level and shared across all instances, while instance attributes are set per object via self.

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