Python Program to check whether a given number is an Armstrong Number or not using lambda and list

Program

num = int(input("Enter a number:\t"))
a = list(map(int,str(num)))
b = list(map(lambda x : x ** 3, a))
if sum(b) == num:
    print(num, "is an armstrong number")
else:
    print(num, "is not an arsmtrong number")

Python Program to Check Whether a Given Number is an Armstrong Number Using Lambda and List

What is an Armstrong Number

An Armstrong number is a number that is equal to the sum of its own digits, each raised to the power of the number of digits.

For a three-digit number, it follows this formula:
abc = a³ + b³ + c³

Examples

• 153 = 1³ + 5³ + 3³ = 153 (Armstrong Number)
• 9474 = 9⁴ + 4⁴ + 7⁴ + 4⁴ = 9474 (Armstrong Number)
• 123 = 1³ + 2³ + 3³ = 36 (Not an Armstrong Number)

1. Take user input

   • num = int(input("Enter a number:\t"))
   • The user enters a number, which is stored in num.

2. Convert number to a list of digits

   • a = list(map(int, str(num)))
   • The number is first converted to a string, then each digit is mapped to an integer, creating a list of digits.

3. Use lambda to compute cubes of digits

   • b = list(map(lambda x: x ** 3, a))
   • The lambda function takes each digit and raises it to the power of three.

4. Check Armstrong condition

   • if sum(b) == num:
   • If the sum of cubes is equal to the original number, it is an Armstrong number.

5. Print the result

   • If the condition is met, the program prints that the number is an Armstrong number; otherwise, it prints that it is not.

Key Takeaways

• The program efficiently converts the number into a list of digits using map and str().
• The lambda function is used to compute the cubes of each digit in a compact way.
• The program checks if the sum of cubes matches the original number to determine if it is an Armstrong number.

Output 1

Enter a number:	89
89 is not an arsmtrong number

Output 2

Enter a number:	407
407 is an armstrong number