Sum of Digits of a Number in Python

Introduction to Sum of Digits of a Number

The goal is to determine the sum of digits of a number given as an input in Python. Example:

Input:

Output:

Input:

Output:

We begin by dividing the number into digits and then adding all of the digits to the sum variable. To break down the string, we use the following operators:

The modulo operator % is used to extract the digits from a number. After removing the digit, we apply the divide operator to shorten the number.

Different Methods to Find Sum of Digits of a Number in Python

Using str() and int() methods

To convert a number to a string, use the str() function. To convert a string digit to an integer, use the int() function.

Convert the number to a string, iterate over each digit in the string, and add to the sum of the digits in each iteration.

Algorithm Flow:

• Step 1: Gather user input.

• Step 2: Create a variable to hold the result.

• Step 3: Convert the number to a string.

• Step 4: Write a loop for each digit in a number.

• Step 5: Convert the digit to an integer and add it to the sum.

• Step 6: Invoke the function and print the result.

Code:

Output:

Using iteration

We shall use loops to calculate the sum of digits of a number. Loops are used to execute a specific piece of code continually. Some looping statements are for loop, while, and do-while.

To find the rightmost digit of an integer, divide the integer by 10 until it equals 0. Finally, the remaining will be the rightmost digit. Use the remaining operator " percent " to receive the reminder. Divide the obtained quotient by 10 to get all the digits of a number. To find the number's quotient, we use “//”.

Algorithm Flow:

• Step 1: Create a function for finding the sum using the parameter n.

• Step 2: Declare a variable sum to store the digit sum.

• Step 3: Create a loop that will run until n is greater than zero.

• Step 4: To the remainder returned by, add the sum variable (n percent 10)

• Step 5: Change n to n/10.

• Step 6: Collect feedback from the user.

• Step 7: Invoke the function defined earlier and pass the input as an argument.

• Step 8: Print the sum of the values returned by the function.

Code:

Output:

Using Recursion

Recursion is the process of defining a problem or the solution to a problem in terms of a simpler version of itself. The corresponding function is called the recursive function. The use of recursion eliminates the requirement for loops in the programming.

Follow the algorithm for a thorough description of how the software works.

Algorithm Flow:

• Step 1: Create a function for finding the sum of digits with the parameter n to compute the sum.

• Step 2: Determine whether n is less than 10; return n.

• Step 3: If not, divide the number by 10 and find the residual (n percent 10)

• Step 4: Recursively call the function and pass (n/10) as a parameter.

• Step 5: Add the remainder and the value returned by the function.

• Step 6: Collect user input.

• Step 7: Invoke the sum of digits function for finding the sum of digits of a number, passing input as a parameter.

Code:

Output:

Using Sum() method

The sum() method is used to compute the sum of digits of a number in python in a list.

Convert the number to a string using str(), then strip the string and convert it to a list of numbers with the strip() and map() methods, respectively. Then, compute the total using the sum() method.

Algorithm Flow:

• Step 1: Create a function for finding the sum of digits with the parameter n to compute the sum.

• Step 2: The number is converted to a string via the str() method.

• Step 3: Then, the string is striped and converted to list digits of the given number via strip() and map() method, respectively.

• Step 4: The sum() method is invoked to compute the total sum of digits.

Code:

Output:

See Also:

• Sum of n natural numbers in python.
• Sum of Prime Numbers in Python.