Python MRO Demonstration (Method Resolution Order)

Aim: Write a Python program to demonstrate the usage of Method Resolution Order (MRO) in multiple levels of Inheritances

Program:


class A:
    def myname(self):
        print(" I am a class A")


class B(A):
    def myname(self):
        print(" I am a class B")


class C(A):
    def myname(self):
        print("I am a class C")

    # classes ordering


class D(B, C):
    pass


d = D()
d.myname()

Output:

I am a class B

Sample Viva Questions and Answers

1. What is the purpose of the program?
The purpose of the program is to demonstrate the Method Resolution Order (MRO) in Python, particularly in the context of multiple inheritance.

2. What is Method Resolution Order (MRO)?
MRO is the order in which classes are searched when executing a method. It determines the sequence in which base classes are looked up for a method.

3. How is the MRO determined in Python?
Python uses the C3 linearization algorithm to determine the MRO, which ensures that the order respects the inheritance hierarchy and the order of base classes.

4. What will be the output of the program when d.myname() is called?
The output will be I am a class B, as class D inherits from class B first, and B has the method myname() that overrides the method in class A.

5. Can you explain the class hierarchy in this program?
The class hierarchy is as follows:

Class A is the base class.
Class B and class C both inherit from class A.
Class D inherits from both class B and class C.

6. What happens if you change the order of inheritance in class D to class D(C, B)?
If you change the order to class D(C, B), the output of d.myname() will be I am a class C, as C will be searched before B in the MRO.

7. How can you view the MRO of a class in Python?
You can view the MRO of a class using the __mro__ attribute or the mro() method. For example, D.__mro__ or D.mro() will show the order in which classes are resolved.

8. What is the significance of method overriding in this context?
Method overriding allows a derived class to provide a specific implementation of a method that is already defined in its base class, affecting the MRO and which method gets called.

9. What will happen if class D does not have any methods defined?
If class D does not have any methods defined, it will inherit methods from its parent classes (B and C). The MRO will still determine which method is called based on the order of inheritance.

10. Can you provide an example of how MRO can lead to ambiguity in method resolution?
MRO can lead to ambiguity if two base classes have methods with the same name and are inherited in a way that does not clearly define which method should be called. Python resolves this using the MRO, but in other languages, it might lead to a conflict.

📌 Python Programming Lab – Complete Guide

Welcome to the Python Programming Lab! This comprehensive lab series is designed to provide a solid foundation in Python programming through practical exercises and hands-on learning. From basic calculations to advanced concepts like file handling, modules, and GUI programming, this lab covers it all. Let’s dive into what you’ll be learning throughout this lab course.

🔍 Week 1: Introduction to Python Basics

In the first week, you will explore fundamental Python concepts aimed at building a strong foundation for your programming journey.

Getting Started with Python: Visit the Python Official Website to explore documentation and use the help() function in the interpreter.
Python as a Calculator: Learn how to perform basic arithmetic operations like addition, subtraction, multiplication, and division.
Calculating Compound Interest: Write a program to calculate compound interest using the formula with given principal, rate, and time.
Distance Calculation: Compute the distance between two points using the distance formula.
Reading User Details: Write a program to collect and print user details like name, address, email, and phone number.

🔍 Week 2: Python Loops and Conditional Statements

This week focuses on using loops and conditional statements effectively.

Pattern Generation: Print a triangle pattern using nested loops.
Character Identification: Write a program to identify whether the input is a digit, lowercase, uppercase, or special character.
Fibonacci Sequence Generation: Use a while loop to generate the Fibonacci series.
Prime Numbers Identification: Find all prime numbers within a specified range using the break statement.

🔍 Week 3: Data Structures and Functions

Dive into data structures and creating functions to enhance your programming skills.

Converting Lists and Tuples to Arrays: Understand how to convert different data structures.
Finding Common Values: Compare two arrays to find common values.
Calculating GCD: Create a function to calculate the greatest common divisor (GCD) of two numbers.
Palindrome Checker: Write a function that checks if a given string is a palindrome.

🔍 Week 4: Advanced Functions and String Manipulation

This week emphasizes sorting, handling duplicate elements, and manipulating strings effectively.

Checking Sorted Lists: Write a function to check if a list is sorted.
Handling Duplicates: Create functions to detect and remove duplicates from lists.
Dictionary Inversion: Write a program to swap keys and values in a dictionary.
String Manipulation: Add commas between characters, remove words from strings, and convert sentences to title case without using built-in functions.
Binary String Generation: Use recursion to generate all binary strings of a specified length.

🔍 Week 5: Working with Matrices and Modules

Learn to work with matrices and create custom modules for various applications.

Matrix Operations: Define, print, add, and multiply square matrices using Python.
Creating Modules: Build modules using geometrical shapes and their operations.
Exception Handling: Implement exception handling for robust error management.

🔍 Week 6: Object-Oriented Programming and Validation

This week focuses on using classes, inheritance, and validation techniques.

Drawing Shapes with Classes:
- Create classes for rectangles, points, and circles, and draw them on a canvas.
- Add colors and attributes to these shapes to enhance visualization.
Method Resolution Order (MRO): Demonstrate MRO in multiple inheritance scenarios.
Data Validation: Write programs to validate phone numbers and email addresses.

🔍 Week 7: File Handling and Text Processing

Master file handling techniques and analyzing text data.

File Merging: Combine the contents of two files into a new file.
Word Search: Create a function to find specific words in a file.
Word Frequency Analysis: Identify the most frequent words in a text file.
Text Statistics: Count words, vowels, blank spaces, lowercase, and uppercase letters in a file.

🔍 Week 8: Python Libraries and GUI Programming

Explore advanced Python libraries and build simple graphical user interfaces.

NumPy, Plotly, and Scipy: Learn how to install and use these powerful libraries for data analysis and visualization.
Digital Logic Gates: Implement logic gate operations such as AND, OR, NOT, and EX-OR.
Adder Circuits: Create programs for Half Adders, Full Adders, and Parallel Adders.
GUI Programming: Build a simple window wizard with text labels, input fields, and buttons using Python’s GUI tools.

🌟 Conclusion:

The Python Programming Lab R23 provides you with a strong foundation in Python programming through a wide range of exercises, from basic concepts to advanced topics. By the end of this lab, you will have gained valuable skills in data processing, file handling, OOP, modules, and GUI development. Start coding and enhance your Python skills! 🚀