🐍 Learn Python · iOS
Learn Python in tiny lessons that actually stick
CodeCub teaches you Python in tiny, deterministic lessons — then makes sure you actually remember it. 54 hand-written lessons, instant on-device checks, and true spaced repetition.
Predict the output
# what does this print? nums = [1, 2, 3] print(sum(nums) * 2)
How CodeCub makes Python stick
Learn in tiny lessons
Each lesson is a single Python concept explained in a few minutes — small enough to finish on a coffee break.
Prove it instantly
Answer a quick check — predict the output, fill the blank, order the lines or pick the answer. Graded on-device, deterministically.
Repetition remembers for you
A true SM-2 scheduler brings each concept back right before you'd forget it, moving it into long-term memory.
54 lessons, 10 tracks
From printing your first line to classes and regex — 54 hand-written lessons across 10 tracks, ordered so each one builds on the last.
Deterministic, on-device grading
Answers are checked against known-correct results on your phone. No AI guessing, no running code on a server — just fast, honest feedback.
True SM-2 spaced repetition
The same algorithm behind serious memory apps schedules every concept for review at the perfect moment, so Python actually stays with you.
Four kinds of check
Predict the output, fill the blank, order the lines, or pick the answer — varied practice that tests real understanding, not memorised clicks.
Real practice
Four ways CodeCub checks you actually get it
Predict the output /predict
Read a snippet and say exactly what it prints — the fastest way to build a mental model of how Python runs.
Fill the blank /fill
Complete the missing token so the code does what the prompt asks. No syntax hand-holding.
Order the lines /order
Drag shuffled lines back into the sequence that produces the right result.
Pick the answer /mc
Choose the correct statement about behaviour, output or a concept.
# fill the blank — make it print HELLO name = "hello" print(name.______()) # → HELLO # answer: upper
Every runnable snippet in CodeCub is verified against real Python — so what you learn is what actually happens.
What you'll learn
All tracks →Ten tracks take you from your first print() to writing classes and regular expressions.
Python Basics
Your first real Python
Strings
Text, sliced and diced
Control Flow & Loops
Decisions and repetition
Lists, Dicts & Data
Collections that hold your data
Functions
Reusable building blocks
Comprehensions
Pythonic one-liners
Errors & Exceptions
When things go wrong
Files & Modules
Beyond a single script
Classes & OOP
Object-oriented Python
Regular Expressions
Pattern matching
Python in your pocket, built to be remembered
- ✓54 hand-written lessons across 10 tracks
- ✓Predict-output, fill-blank, order-lines & multiple-choice checks
- ✓Deterministic grading on-device — no AI, no server
- ✓True SM-2 spaced repetition brings concepts back on time
- ✓A daily review reminder tuned to what's actually due
- ✓Free, and no account needed to start
Today · 4 due
for loops
Control Flow · Due now
Dictionaries
Data · In 2 days
f-strings
Python Basics · In 5 days
Questions, answered
Is CodeCub free?+
Yes — CodeCub is free on the App Store. You get 54 hand-written Python lessons across 10 tracks with no account required to start.
Do I need any coding experience?+
No. CodeCub starts from printing your first line of output and builds up in tiny steps, so complete beginners and self-learners can follow along a few minutes at a time.
How does CodeCub make Python stick?+
Every concept is scheduled with a true SM-2 spaced-repetition algorithm. CodeCub brings each idea back exactly when you're about to forget it, so it moves into long-term memory instead of leaking away.
How are my answers graded?+
Deterministically, on your device. CodeCub checks predict-the-output, fill-the-blank, order-the-lines and multiple-choice exercises against known-correct answers — no AI guessing and no running your code on a server.
What will I be able to do after finishing?+
You'll be comfortable with Python variables, strings, control flow and loops, lists and dictionaries, functions, comprehensions, error handling, files and modules, classes (OOP) and basic regular expressions.
Start Python the way you'll remember it
Tiny lessons, honest on-device checks, and spaced repetition that keeps it all in your head. Free on the App Store.