Python: Sum all the items in a list

Last update on April 19 2025 13:02:51 (UTC/GMT +8 hours)

Sum Items in List

Write a Python program to sum all the items in a list.

Visual Presentation:

Sample Solution:

Python Code:

# Define a function called sum_list that takes a list 'items' as input
def sum_list(items):
    # Initialize a variable 'sum_numbers' to store the sum of the numbers
    sum_numbers = 0
    # Iterate through each element 'x' in the input list 'items'
    for x in items:
        # Add the current element 'x' to the 'sum_numbers' variable
        sum_numbers += x
    # Return the final sum of the numbers
    return sum_numbers

# Call the sum_list function with the list [1, 2, -8] as input and print the result
print(sum_list([1, 2, -8]))

Sample Output:

-5

Explanation:

In the above exercise -

def sum_list(items): -> This line defines a function called “sum_list” that takes a single argument items. This function will be used to calculate the sum of all the numbers in the items list.

sum_numbers = 0 -> This line initializes a variable called sum_numbers to zero. This variable will be used to keep track of the running total of the sum of the numbers in the list.
for x in items: -> This line starts a loop that will iterate over each element in the items list, one at a time.
sum_numbers += x -> This line adds the current value of x to the sum_numbers variable. This is equivalent to the shorter form sum_numbers = sum_numbers + x.
return sum_numbers -> This line returns the final value of the sum_numbers variable after the loop has finished.

print(sum_list([1,2,-8])) -> This line calls the sum_list function and passes in the list [1,2,-8]. The resulting sum is then printed to the console using the print() function.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to find the sum of only the positive numbers in a given list.
Write a Python program to sum all numbers in a list except those that are multiples of 3.
Write a Python program to find the sum of numbers in a nested list.
Write a Python program to find the sum of the digits of each element in a list.

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