Day 12: List Loops — Visit Every Item Automatically!

The Problem Without List Loops

Imagine a delivery person with 100 packages. They visit every house one by one — no house gets skipped. That's exactly what a list loop does! Instead of printing every item manually, the loop visits each one automatically.

Your First List Loop

fruits = ["Apple", "Mango", "Banana"]

for fruit in fruits:
    print(fruit)

Output: Apple, Mango, Banana. The loop visits Apple first, then Mango, then Banana. fruit is just a temporary name for whichever item the loop is currently visiting!

How It Works

for = start the loop. fruit = the current item being visited. in fruits = take items from this list. Each round, fruit becomes the next item in the list until every item is visited!

Real World Connection

When Instagram loads your feed, it loops through a list of posts and displays each one. When Swiggy shows your order history, it loops through a list of past orders. When PUBG checks which players are still alive, it loops through the player list. List loops power everything!

Do Things With Each Item

scores = [85, 92, 67, 78]

for score in scores:
    if score >= 90:
        print(score, "Excellent!")
    else:
        print(score, "Good!")

Loop + condition together! This checks every score and gives feedback. This is exactly how your school's result system works!

Common Mistakes

Mistake 1 — Missing the keyword "in".

for fruit fruits:
for fruit in fruits:

Mistake 2 — Wrong indentation.

for fruit in fruits:
print(fruit)

for fruit in fruits:
    print(fruit)

Mini Challenge

Quick Quiz

Q: What does "fruit" represent in "for fruit in fruits"? A: The current item being visited in that loop round!

Q: Does a list loop skip any items? A: Never! Every single item gets visited.

Q: What two things must every list loop have? A: The keyword "in" and indentation inside the loop!

Key Takeaways