Python Program to Check Happy Number

Posted in Python Tutorial

Updated on Oct 31, 2024

By Mari Selvan

👁️ 185 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the domain of programming, certain mathematical properties and patterns are often explored. One such interesting concept is the notion of "happy numbers."

In this tutorial, we'll delve into a Python program designed to determine whether a given number is a happy number.

📄 Example

Let's take a look at the Python code that checks whether a given number is a happy number or not.

is_happy_number.py

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# Function to calculate the sum of squares of digits
def sum_of_squares(n):
    sum_val = 0
    while n > 0:
        digit = n % 10
        sum_val += digit * digit
        n //= 10
    return sum_val

# Function to check if a number is a happy number
def is_happy_number(n):
    slow = n
    fast = n
    while True:
        slow = sum_of_squares(slow)
        fast = sum_of_squares(sum_of_squares(fast))
        if slow == fast:
            break
    return slow == 1

# Driver program
if __name__ == "__main__":
    # Replace this value with your desired number
    number = 19

    # Check if the number is a happy number
    if is_happy_number(number):
        print(f"{number} is a Happy Number.")
    else:
        print(f"{number} is not a Happy Number.")

💻 Testing the Program

To test the program with a different number, replace the value of number in the if __name__ == "__main__": block.

Output

19 is a Happy Number.

Run the script to check if the number is a happy number.

🧠 How the Program Works

The program defines a function sum_of_squares to calculate the sum of the squares of digits of a given number.
It then defines a function is_happy_number that checks whether a given number is a happy number using Floyd's cycle detection algorithm.
The if __name__ == "__main__": block tests the program with a sample number (in this case, 19).

📏 Between the Given Range

Let's take a look at the python code that checks for Happy Numbers in the specified range.

is_happy_number.py

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def is_happy_number(num):
    seen = set()
    while num != 1 and num not in seen:
        seen.add(num)
        num = sum(int(digit) ** 2 for digit in str(num))
    return num == 1

# Identify Happy Numbers in the range 1 to 50
happy_numbers = [num for num in range(1, 51) if is_happy_number(num)]

# Print the results
print("Happy numbers in the range 1 to 50:")
for num in happy_numbers:
    print(num, end=" ")

💻 Testing the Program

Output

Happy numbers in the range 1 to 50:
1 7 10 13 19 23 28 31 32 44 49

Simply run the script to see the Happy Numbers in the range of 1 to 50.

🧠 How the Program Works

The program defines a function is_happy_number that checks whether a given number is a Happy Number.
Inside the function, it uses a while loop to iterate through the Happy Number sequence until reaching 1 or encountering a previously seen number.
The main section identifies and prints the Happy Numbers in the specified range (1 to 50).

🧐 Understanding the Concept of Happy Number

A happy number is a positive integer defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1, or it loops endlessly in a cycle that does not include 1.

For example, let's take the number 19:

1²+9² = 82
8²+2² = 68
6²+8² = 100
1²+0²+0² = 1

In this case, 19 is a happy number because the process ends with 1.

🎢 Optimizing the Program

While the provided program is effective, there are various ways to optimize and enhance it further. Consider exploring different algorithms or incorporating additional features based on your specific requirements.

Feel free to incorporate and modify this code as needed for your specific use case. Happy coding!