Coding for Kids · Lesson

A Loop Inside a Loop

Loops within loops.

A Loop Inside a Loop is a free Coding for Kids lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Coding for Kids learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Loops Are Awesome! 🔁

Hi superstar! 🌟 You already know a loop repeats things. Today we learn something SUPER cool: a loop inside another loop!

It's like a robot doing a little dance over and over, while a bigger robot makes it dance again and again! 🤖

for i in range(3):
    print('Outer loop! 🤖')

What Is Nesting? 🪺

When you put one loop inside another, we call it a nested loop. Just like a tiny bird's nest sitting inside a big tree! 🪺🌳

The inside loop finishes ALL its turns before the outside loop moves on.

for big in range(2):
    for small in range(2):
        print('hello!')

Counting With Two Loops 🔢

Let's watch the numbers! The outer loop picks a number, then the inner loop runs all the way through before going back up.

Outer = the big steps
Inner = the little steps

for a in range(2):
    for b in range(3):
        print('a =', a, 'b =', b)

Indenting Matters! ➡️

In Python, the spaces in front of code tell it where it belongs. The inner loop's code is pushed in even MORE! ➡️➡️

Think of it like stairs going down. Each loop is one more step in!

for x in range(2):
    print('Step in once')
    for y in range(2):
        print('    Step in twice!')

Stars and Stars ⭐

Let's make rows of stars! The outer loop makes a new row, and the inner loop prints stars on that row. ⭐⭐⭐

We use end='' so stars stay on the same line!

for row in range(3):
    for star in range(4):
        print('*', end='')
    print()

Robot Dance Party 🕺

Imagine 3 robots. Each robot spins around 2 times. How many spins is that all together? Let's let the computer count for us!

for robot in range(3):
    print('Robot', robot + 1, 'is dancing!')
    for spin in range(2):
        print('  spin!')

Inner Finishes First 🏁

Here's the secret rule: the inner loop runs completely for every single turn of the outer loop. 🏁

So if outer runs 2 times and inner runs 3 times, that's 2 × 3 = 6 total prints!

count = 0
for a in range(2):
    for b in range(3):
        count = count + 1
print('Total runs:', count)

Naming Your Loops 🏷️

You can name your loop helpers anything! People often use i and j as short names. ✏️

But row and col are even friendlier names. Pick whatever helps you understand! 😊

for i in range(2):
    for j in range(2):
        print('i and j:', i, j)

Make a Box 📦

With two loops we can draw a little box of hashes! The outer loop is the number of rows, the inner loop fills each row. 📦

for row in range(3):
    for col in range(5):
        print('#', end='')
    print()

Loops Inside Loops Inside... 🌀

You can even put a loop inside a loop inside a loop! But let's keep it to two for now. Three is super dizzy! 🌀

Most cool patterns only need TWO loops. Nice and simple!

for a in range(2):
    for b in range(2):
        print('Pair:', a, b)

Your Turn to Imagine ✨

Try changing the numbers in range() and see what happens! Bigger numbers = more rows and more stars. ✨

Playing and changing things is how the best coders learn! 🚀

for row in range(4):
    for star in range(6):
        print('+', end='')
    print()

Quick Check! 🧠

Time for a fun question! Think about how nested loops count. 🤔

You Did It! 🎉

Wow, you learned nested loops! 🎉

A loop inside a loop is called nested 🪺
The inner loop finishes before the outer moves on 🏁
Indenting (spaces) tells loops where they belong ➡️
Multiply the turns to count total runs 🔢

Next up: drawing cool grids! 🟦

for row in range(2):
    for col in range(3):
        print('🌟', end='')
    print()

Frequently asked questions

Is the “A Loop Inside a Loop” lesson free?

Yes — the full text of “A Loop Inside a Loop” is free to read here on the web, and the Coding for Kids course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Coding for Kids course, upgrade to CoddyKit PRO.

What will I learn in “A Loop Inside a Loop”?

Loops within loops. You practise Coding for Kids with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Coding for Kids?

No prior experience is required. Coding for Kids on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “A Loop Inside a Loop” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Coding for Kids lesson?

Yes. Every Coding for Kids lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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