Repeat with for and range

A for loop repeats its indented block for each value from an iterable. range(1, 4) produces 1, 2, and 3: the stop value is excluded.

for day in range(1, 4):
    print(f"Day {day}")

Day 1
Day 2
Day 3

Keep a running total

Create the total before the loop. Then add each value while the loop runs. The += operator is shorthand for assigning total + value back to total.

total = 0
for day in range(1, 4):
    total += day * 10
print(total)

60

Why this works

range(start, stop) generates a sequence of integers up to, but not including, stop. The loop variable receives one value at a time, then the indented body runs. A running total must be created before the loop; otherwise it would not preserve the sum of earlier iterations.

Practice

Use range(1, 6) to print days 1 through 5. Then add 15 minutes for each day to a running total and print 75.

Try another case

How many times does for day in range(2, 6) run, and which values appear?