Python Program for Sum the digits of a given number

Given a number and the task is to find sum of digits of this number in Python. 
Examples:

Input : n = 87 
Output : 15 
Input : n = 111 
Output : 3

Below are the methods to sum of the digits. 
Method-1: Using str() and int() methods.: The str() method is used to convert the number to string. The int() method is used to convert the string digit to an integer. 

Convert the number to string and iterate over each digit in the string and after converting each digit to integer and add to the sum of the digits in each iteration. 

Python3

# Python program to
# compute sum of digits in
# number.

# Function to get sum of digits
def getSum(n):

    sum = 0
    for digit in str(n):
      sum += int(digit)
    return sum

n = 12345
print(getSum(n))

Output:

15

Method-2: Using sum() methods.: The sum() method is used to sum of numbers in the list.

Convert the number to string using str() and strip the string and convert to list of number using strip() and map() method resp. Then find the sum using the sum() method.

Python3

# Python program to
# compute sum of digits in
# number.

# Function to get sum of digits
def getSum(n):

    strr = str(n)
    list_of_number = list(map(int, strr.strip()))
    return sum(list_of_number)

n = 12345
print(getSum(n))

Output:

15

Method-3: Using General Approach: 

• Get the number
• Declare a variable to store the sum and set it to 0
• Repeat the next two steps till the number is not 0
• Get the rightmost digit of the number with help of remainder ‘%’ operator by dividing it with 10 and add it to sum.
• Divide the number by 10 with help of ‘//’ operator
• Print or return the sum

A. Iterative Approach:

Python3

# Python 3 program to
# compute sum of digits in
# number.

# Function to get sum of digits
def getSum(n):

    sum = 0
    while (n != 0):

        sum = sum + (n % 10)
        n = n//10

    return sum

n = 12345
print(getSum(n))

Output:

15

B. Recursive Approach:

Python3

# Python program to compute
# sum of digits in number.

def sumDigits(no):
    return 0 if no == 0 else int(no % 10) + sumDigits(int(no / 10))

# Driver code
n = 12345
print(sumDigits(n))

Output:

15