Stats

Loops can be used to calculate statistics of a list (or an iterator) of numbers. Let's see how we can calculate the sum, minimum, and maximum of a list of numbers.

Sum

To calculate sum of a list of numbers, we can use a for loop to iterate over the list and add each number to a variable that keeps track of the sum. Here's an example:

sum_of_numbers = 0

for num in range(1, 101):
    sum_of_numbers += num

print(f"Sum: {sum_of_numbers}")
print(f"Average: {sum_of_numbers / 100}")

Not that at the last line we also calculate the average of the numbers by dividing the sum by the length of the list.

Output of the program:

Sum: 5050
Average: 50.5

Minimum and Maximum

Here's how we can calculate the minimum and maximum of a list of numbers:

numbers = [10, 6, 2, 3, 9, 0, 5, 7, 1, 4, 8]

min = numbers[0]
max = numbers[0]

for number in numbers:
    if number < min:
        min = number
    if number > max:
        max = number

print(f"Min: {min}")
print(f"Max: {max}")

We first initialize the minimum and maximum to the first element of the list. Then we iterate over the list and update the minimum and maximum if we find a smaller or larger number. Finally, we print the minimum and maximum:

Min: 0
Max: 10

Notice how we use the if statement inside the for loop.

Built-in Functions

In practice, we don't need to write our own functions to calculate the sum, minimum, and maximum of a list of numbers. Python provides built-in functions for these purposes. Here's how we could use them:

numbers = [1, 2, 3, 4, 5]

print("Sum:", sum(numbers))
print("Min:", min(numbers))
print("Max:", max(numbers))

and here's the output:

Sum: 15
Min: 1
Max: 5

In general, in programming it's a good idea to use built-in functions whenever possible. They are usually faster and more reliable than our own functions.