Loops

A for loop steps through a sequence — often the result of range(n), which produces the numbers 0 up to (not including) n.

Example: summing a range

total = 0
for i in range(1, 6):
    total += i

print("Total:", total)

Total: 15

range(1, 6) produces 1, 2, 3, 4, 5 — the second number is the stopping point, not included, which trips up nearly every beginner at least once. A while loop, by contrast, repeats as long as its condition stays true, and is the better tool whenever you don't know the number of iterations in advance.