🔁 Loops: for and while

for with range

for i in range(5):
    print("Hello", i)
# prints Hello 0 … Hello 4

range(5) gives 0, 1, 2, 3, 4 — five numbers, starting at 0. range(1, 11) gives 1 to 10. range(0, 20, 5) gives 0, 5, 10, 15.

Adding up in a loop

total = 0
for n in range(1, 101):
    total += n
print(total)  # 5050

while

answer = ""
while answer != "yes":
    answer = input("Are we there yet? ")
print("Finally!")

while repeats as long as the condition is true. Use it when you don’t know how many times in advance.

break and infinite loops

break leaves a loop immediately. If a while condition never becomes false, the loop runs forever — press Ctrl+C or the stop button to break out, then fix the condition.

Tip

💡 Use for when you know how many times; use while when you repeat “until something happens”.

🧠 Quick quiz

Answer all 4 questions correctly to mark this lesson as done.