Lists & Loops

Lists are used for representing a collection of values.

numbers = [1, 2, 3, 4, 5]
print(numbers)

We use a for loop to iterate over a list of values.

numbers = [1, 2, 3, 4, 5]
for n in numbers:
    print(n)

Try changing the above program to print the squares of numbers instead of the numbers.

We can find the length of a list using the built-in function len.

numbers = [1, 2, 3, 4, 5]
print(len(numbers))

Example: sum

Pytho has a built-in function sum to compute the sum of a list of numbers.

numbers = [1, 2, 3, 4, 5]
print(sum(numbers))

Let's try to implement our own version of sum. Let's call it my_sum.

def my_sum(values):
    result = 0
    for v in values:
        result = result + v
    return result

numbers = [1, 2, 3, 4, 5]
print(my_sum(numbers))

Can you write a function product to compute the product.

def product(values):
    # FIX ME
    return 0

numbers = [1, 2, 3, 4, 5]
print(product(numbers))