Welcome to the Python OOPs Concepts Python Interview Questions! Object-Oriented Programming (OOP) is a powerful paradigm in Python that allows you to create classes and objects, encapsulate data and methods, and implement inheritance, polymorphism, and abstraction. These questions will test your understanding of various OOP concepts in Python, including classes, objects, inheritance, encapsulation, and polymorphism. Each question is multiple-choice, with only one correct answer. Take your time to carefully read each question and choose the best option. Let’s dive into the world of Python OOPs concepts together!
30+ Python Interview Questions on Python OOPs Concepts
Q1. What is OOP?
a) Out-of-Order Processing
b) Object-Oriented Programming
c) Out-of-Place Programming
d) Optimized Object Parsing
Answer: b
Explanation: OOP stands for Object-Oriented Programming, a programming paradigm based on the concept of “objects”.
Q2. What is an object in OOP?
a) A variable
b) A block of code
c) An instance of a class
d) A built-in function
Answer: c
Explanation: In OOP, an object is an instance of a class. It encapsulates data for the class and provides methods to access and modify that data.
Q3. Which of the following is NOT a basic principle of OOP?
a) Encapsulation
b) Inheritance
c) Polymorphism
d) Concatenation
Answer: d
Explanation: Concatenation is not a basic principle of OOP. Encapsulation, inheritance, and polymorphism are core principles.
Q4. What is inheritance in OOP?
a) The ability to create new classes from existing ones
b) The ability to access private members of a class
c) The ability to create objects
d) The ability to override methods
Answer: a
Explanation: Inheritance allows a new class (subclass) to inherit properties and behavior (methods) from an existing class (superclass).
Q5. Which keyword is used to inherit a class in Python?
a) extends
b) inherit
c) superclass
d) class
Answer: a
Explanation: In Python, the extends keyword is used for inheritance. The subclass extends the superclass.
Q6. What is encapsulation in OOP?
a) Hiding the implementation details of an object
b) Making an object public
c) Exposing private data of an object
d) Limiting the number of objects
Answer: a
Explanation: Encapsulation is the bundling of data (attributes) and methods (functions) that operate on the data, hiding the implementation details from the user.
Q7. Which access specifier in Python indicates that an attribute should not be accessed directly from outside the class?
a) public
b) private
c) protected
d) hidden
Answer: b
Explanation: In Python, an attribute or method with a name starting with two underscores __ is considered private and should not be accessed directly from outside the class.
Q8. What is polymorphism in OOP?
a) The ability of an object to take on many forms
b) The ability to inherit from multiple classes
c) The ability to have multiple constructors
d) The ability to have multiple instances of an object
Answer: a
Explanation: Polymorphism refers to the ability of an object to take on many forms. It allows objects of different classes to be treated as objects of a common superclass.
Q9. Which OOP principle allows methods in a subclass to have the same name as methods in its superclass, but with different implementations?
a) Inheritance
b) Polymorphism
c) Encapsulation
d) Abstraction
Answer: b
Explanation: Polymorphism allows methods in a subclass to have the same name as methods in its superclass, but with different implementations.
Q10. What is the process of defining a new class based on an existing class called?
a) Polymorphism
b) Inheritance
c) Abstraction
d) Encapsulation
Answer: b
Explanation: Inheritance is the process of defining a new class based on an existing class, inheriting its attributes and methods.
Q11. What is a superclass in inheritance?
a) A class that does not have any parent class
b) A class from which other classes inherit
c) A class that can inherit from multiple classes
d) A class with private attributes only
Answer: b
Explanation: A superclass (or parent class) is a class from which other classes inherit properties and behaviors.
Q12. What is a subclass in inheritance?
a) A class that does not have any child class
b) A class that has a parent class
c) A class that cannot have private attributes
d) A class that can inherit from multiple classes
Answer: a
Explanation: A subclass (or child class) is a class that inherits properties and behaviors from a superclass.
Q13. Which of the following is true about the super() function in Python?
a) It calls the superclass’s constructor
b) It calls the subclass’s constructor
c) It is used to create a new object
d) It is used to access private members
Answer: a
Explanation: The super() function in Python is used to call methods and constructors of the superclass.
Q14. What is method overriding in OOP?
a) Creating a new method with the same name as a method in the superclass
b) Deleting a method from a superclass
c) Hiding a method in the superclass
d) Replacing a method in the superclass with a new implementation in the subclass
Answer: d
Explanation: Method overriding occurs when a subclass provides a specific implementation of a method that is already defined in its superclass.
Q15. What is an abstract class in Python?
a) A class that cannot be instantiated
b) A class with only private methods
c) A class with only public methods
d) A class with no methods
Answer: a
Explanation: An abstract class in Python is a class that cannot be instantiated and is used as a base class for other classes.
Q16. How do you define an abstract class in Python?
a) By using the abstract keyword
b) By using the abstract class statement
c) By importing the abc module and using @abstractmethod decorator
d) By using the virtual keyword
Answer: c
Explanation: Abstract classes in Python are defined by importing the abc module and using the @abstractmethod decorator.
Q17. What is an interface in Python?
a) A class that cannot be inherited
b) A blueprint of a class without any implementation
c) A class with only private methods
d) A class with only public methods
Answer: b
Explanation: An interface in Python is a blueprint of a class that defines a set of methods without any implementation.
Q18. Which OOP principle allows a class to have multiple methods with the same name but different parameters?
a) Inheritance
b) Polymorphism
c) Encapsulation
d) Abstraction
Answer: b
Explanation: Polymorphism allows a class to have multiple methods with the same name but different parameters or behavior.
Q19. What is composition in OOP?
a) A way to create objects of one class within another class
b) A way to create multiple instances of a class
c) A way to inherit from multiple classes
d) A way to override superclass methods in a subclass
Answer: a
Explanation: Composition is a design technique in OOP where objects of one class are created within another class.
Q20. What is the purpose of the __init__ method in Python classes?
a) To define private attributes
b) To define public attributes
c) To initialize object state
d) To delete an object
Answer: c
Explanation: The __init__ method is a special method in Python classes used to initialize newly created objects with initial values.
Q21. Which keyword is used to define a method in a Python class?
a) method
b) def
c) define
d) function
Answer: b
Explanation: The def keyword is used to define a method within a Python class.
Q22. What does the self keyword represent in Python class methods?
a) It represents the superclass
b) It represents the subclass
c) It represents the current object instance
d) It represents the class itself
Answer: c
Explanation: In Python class methods, self represents the current object instance and allows access to its attributes and methods.
Q23. What does the __str__ method do in Python?
a) Converts an object to a string
b) Converts a string to an object
c) Compares two objects
d) Initializes an object
Answer: a
Explanation: The __str__ method in Python is a special method used to return a string representation of an object.
Q24. Which method is called when an object is deleted?
a) __delete__
b) __remove__
c) __del__
d) __destroy__
Answer: c
Explanation: The __del__ method is called when an object is deleted or garbage-collected in Python.
Q25. What does the isinstance() function do in Python?
a) Checks if an object is an instance of a specific class
b) Checks if an object is a subclass of a specific class
c) Checks if two objects are equal
d) Checks if two objects are the same instance
Answer: a
Explanation: The isinstance() function in Python checks if an object is an instance of a specific class or a subclass.
Q26. What does the issubclass() function do in Python?
a) Checks if an object is an instance of a specific class
b) Checks if an object is a subclass of a specific class
c) Checks if two objects are equal
d) Checks if two objects are the same instance
Answer: b
Explanation: The issubclass() function in Python checks if a class is a subclass of another class.
Q27. What is the purpose of the @staticmethod decorator in Python?
a) To create a static method that can access class attributes
b) To create a method that can access instance attributes
c) To create a class method that can access instance attributes
d) To create a method that can access both class and instance attributes
Answer: a
Explanation: The @staticmethod decorator in Python is used to define a static method that does not have access to instance attributes.
Q28. What is the purpose of the @classmethod decorator in Python?
a) To create a static method that can access class attributes
b) To create a method that can access instance attributes
c) To create a class method that can access class attributes
d) To create a method that can access both class and instance attributes
Answer: c
Explanation: The @classmethod decorator in Python is used to define a class method that has access to class attributes.
Q29. What does the super() function do in Python?
a) Calls the superclass’s method
b) Calls the subclass’s method
c) Creates a new object
d) Deletes an object
Answer: a
Explanation: The super() function in Python is used to call methods of a superclass from a subclass.
Q30. What does the term “method resolution order” (MRO) refer to in Python?
a) The order in which methods are defined in a class
b) The order in which methods are called in a class
c) The order in which multiple inheritance searches for a method
d) The order in which classes are defined in a module
Answer: c
Explanation: Method Resolution Order (MRO) in Python refers to the order in which multiple inheritance searches for a method or attribute.
Q31. What does the following Python code represent?
class Student:
def __init__(self, name, age):
self.name = name
self.age = age
def display_info(self):
print("Name:", self.name)
print("Age:", self.age)
student1 = Student("John", 20)
student1.display_info()
a) Definition of a Student class with attributes name and age
b) Creation of a Student object student1 with name “John” and age 20
c) Displaying information about the student
d) All of the above
Answer: d
Explanation: This code defines a Student class with __init__ method to set name and age, and a method display_info to print student information. It creates a Student object student1 with name “John” and age 20, then displays its information by calling display_info().
Q32. What will be the output of the following code?
class Shape:
def __init__(self, sides):
self.sides = sides
def display_sides(self):
print("Number of sides:", self.sides)
class Triangle(Shape):
def __init__(self, side1, side2, side3):
super().__init__(3)
self.side1 = side1
self.side2 = side2
self.side3 = side3
def display_area(self):
s = (self.side1 + self.side2 + self.side3) / 2
area = (s * (s - self.side1) * (s - self.side2) * (s - self.side3)) ** 0.5
print("Area of the triangle:", area)
triangle1 = Triangle(3, 4, 5)
triangle1.display_sides()
triangle1.display_area()
a) Number of sides: 3 Area of the triangle: 6.0
b) Number of sides: 3 Area of the triangle: 7.5
c) Number of sides: 4 Area of the triangle: 6.0
d) Number of sides: 4 Area of the triangle: 7.5
Answer: a
Explanation: The code defines a Shape class with __init__ method for sides and a method display_sides to print the number of sides. It then defines a Triangle subclass that inherits from Shape, sets the number of sides to 3, and calculates the area based on side lengths. When a Triangle object triangle1 is created with sides 3, 4, and 5, it prints the number of sides and the area, which is 6.0 for this case.
Q33. What will be the output of the following code?
class Student:
def __init__(self, name, roll_number):
self.name = name
self.roll_number = roll_number
def display_student(self):
print("Name:", self.name)
print("Roll Number:", self.roll_number)
student1 = Student("Alice", 101)
student1.display_student()
a) Name: Alice Roll Number: 101
b) Alice 101
c) Student: Alice ID: 101
d) Name: Student Roll Number: Alice 101
Answer: a
Explanation: The code defines a Student class with __init__ method to set name and roll_number, and a method display_student to print student information. It creates a Student object student1 with name “Alice” and roll number 101, then displays its information by calling display_student().
Congratulations on completing the Python OOPs Concepts MCQs! Object-Oriented Programming is a fundamental concept in Python, allowing you to create efficient and scalable code by organizing data and behavior into classes and objects. By mastering OOP concepts such as inheritance, encapsulation, and polymorphism, you gain the ability to design and implement complex and reusable software systems. Keep practicing and experimenting with Python’s OOP functionalities to become proficient in building robust and maintainable applications. If you have any questions or want to delve deeper into any topic, don’t hesitate to continue your learning journey. Happy coding!
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