How to Count Matching Characters in a Pair of Strings in Python

Submitted by razormist on Thursday, May 21, 2026 - 23:40.

In this tutorial, we will learn how to program "How to Count Matching Characters in a Pair of Strings in Python". The objective is to count matching characters in a pair of strings. This tutorial will guide you step by step through the process of counting matching characters. By the end of this tutorial, you will have a solid understanding of how to implement this solution effectively in Python, helping you strengthen your problem-solving abilities and improve your coding skills.

This topic is straightforward and easy to understand. By following the instructions provided, you will be able to complete it with ease. The program will guide you step by step through the process of counting matching characters in a pair of strings. So, let’s dive into the coding process!

Getting Started:

First you will have to download & install the Python IDLE's, here's the link for the Integrated Development And Learning Environment for Python https://www.python.org/downloads/.

Creating Main Function

This is the main function of the application. The following code will display a simple GUI in terminal console that will display program. To do this, simply copy and paste these blocks of code into the IDLE text editor.

# MAIN LOOP
while True:
    print("\n============= Count Matching Characters in a Pair of Strings =============\n")
 
    # Input strings
    s1 = input("Enter first string: ").strip()
    s2 = input("Enter second string: ").strip()
 
    # Validation
    if not s1 or not s2:
        print("Strings cannot be empty.")
        continue
 
    print(f"\nFirst String:  {s1}")
    print(f"Second String: {s2}")
 
    # Find matching characters
    matching_chars = set(s1.lower()) & set(s2.lower())
 
    # Count matching characters
    res = len(matching_chars)
 
    print(f"\nMatching characters: {matching_chars}")
    print(f"Number of matching characters: {res}")
 
    # Try Again Option
    opt = input("\nDo you want to try again? (yes/no): ").strip().lower()
 
    if opt == 'no':
        print("Exiting program...")
        break
    elif opt != 'yes':
        print("Invalid choice. Exiting program...")
        break

This Python program counts the matching characters between two strings by comparing their unique characters in a case-insensitive manner. It accepts two user-input strings, converts them to lowercase, and uses set intersection to find common characters shared by both strings. The program then displays the matching characters along with their total count. It includes input validation and runs interactively, allowing users to repeat the process or exit.

Output:

There you have it we successfully created How to Count Matching Characters in a Pair of Strings in Python. I hope that this simple tutorial help you to what you are looking for. For more updates and tutorials just kindly visit this site. Enjoy Coding!

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