We’ll see different ways to find sum of elements in a list. The requirement is that if a list contains numbers, then find the sum of all the elements in the list.

Input: [3, 10, 15, 35, 55]
Output: 118

We’ll discuss four ways to find the sum of all the elements in the list:

• Using sum() method
• Using for loop
• Using while loop
• Using recursive method

Method 1: Using sum() method

We can pass list as an argument to the sum() method. This is easiest way to find the sum of elements of a list.

# Python program to find sum of elements in list using sum()

# create list
listOfNumbers = [3, 10, 15, 35, 55]

# calculate sum using sum() method
sum = sum(listOfNumbers)
print("sum of elements:",sum)

Output

sum of elements: 118

Method 2: Using for loop

In this method, we’ll initialize sum to zero. We then iterate the elements of the list using for loop and add each element to the sum.

# Python program to find sum of elements in list using for loop

sum = 0

# create list
listOfNumbers = [3, 10, 15, 35, 55]

for element in listOfNumbers:
    sum = sum + element

print('sum of elements:',sum)

Output

sum of elements: 118

Method 3: Using while loop

In this method, we’ll initialize sum to zero. We then iterate the elements of the list using for while loop based on index of elements and add each element to the sum.

# Python program to find sum of elements in list using while

sum = 0
index = 0
# create list
listOfNumbers = [3, 10, 15, 35, 55]

# Iterate elements of list based on index
# and add every element to sum
while(index < len(listOfNumbers)):
    sum = sum + listOfNumbers[index]
    index += 1

print('sum of elements:',sum)

Output

sum of elements: 118

Method 4: Using recursive method

In this method, we’ll use recursive method to calculate the sum of elements of a list.

# Python program to find sum of all
# elements in list using recursion
 
# creating a list
listOfNumbers = [3, 10, 15, 35, 55]
 
# recursive function to find sum of elements
def sumOfElements(list, size):
   if (size == 0):
     return 0
   else:
     return list[size - 1] + sumOfElements(list, size - 1)
  
# Driver code    
total = sumOfElements(listOfNumbers, len(listOfNumbers))
 
print("Sum of elements: ", total)

Output

sum of elements: 118