Loops: Do It Again! 🔁

What if you need to do something many times — like adding up 100 numbers, or checking every item in a list? You don't write the same line 100 times. You use a loop!

for loops

A for loop repeats code once for every item in something, like a range of numbers or a list:

for i in range(5):
    print(i)
# prints 0, 1, 2, 3, 4

range(5) means "the numbers 0 up to (but not including) 5." You can also loop directly over a list:

for fruit in ["apple", "banana", "cherry"]:
    print(fruit)

A super common pattern is building up a total inside a loop:

total = 0
for n in [1, 2, 3]:
    total = total + n
print(total)  # 6

while loops

A while loop keeps repeating as long as a condition stays True:

count = 0
while count < 3:
    print(count)
    count = count + 1

Be careful with while loops — if the condition never becomes False, your loop will run forever! Always make sure something inside the loop is working toward ending it.

Let's practice both kinds!