How to Find Odd Occurring Number in a List in Python

Submitted by razormist on Monday, April 27, 2026 - 23:33.

In this tutorial, we will learn how to program "How to Find Odd Occurring Number in a List in Python". The objective is to find the odd-occurring number in a list. This tutorial will guide you step by step through the process of identifying the element that appears an odd number of times. 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 finding the odd-occurring number in a list. 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.

def find_odd_occurring(alist):
    """Return the element that occurs odd number of times."""
    ans = 0
    for element in alist:
        ans ^= element
    return ans
 
 
# MAIN LOOP
while True:
    print("\n============= Find Odd Occurring Number in a List =============\n")
 
    # Input handling
    try:
        user_input = input("Enter numbers (space-separated): ").strip()
        if not user_input:
            print("Input cannot be empty.")
            continue
 
        alist = [int(i) for i in user_input.split()]
    except ValueError:
        print("Invalid input. Please enter integers only.")
        continue
 
    # Run algorithm
    ans = find_odd_occurring(alist)
 
    print(f"\nThe element that occurs odd number of times: {ans}")
 
    # 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 finds the element that occurs an odd number of times in a list using the XOR operation. It defines a function that iterates through the list and applies XOR to all elements, effectively canceling out even occurrences and leaving the odd one. The program runs interactively, allowing users to input a list of integers, display the result, and repeat the process or exit, with input validation included.

Output:

There you have it we successfully created How to Find Odd Occurring Number in a List 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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