Writing Idiomatic Python
Transform clunky, procedural script code into elegant, maintainable Python. Master lazy evaluation, function ergonomics, context managers, and the native data model.
Like Duolingo, but for Writing Idiomatic Python. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
A short one: 10 levels across 2 sections, about 20 minutes end to end, roughly 4 days at five minutes a day. It moves through Expressive Control and Functions and Resource Management and the Object Model. It assumes you already know the basics.
Free forever · No credit card · iPhone & Android
Key ideas in Writing Idiomatic Python
- Python's zip combines multiple iterables into tuples element-by-element without indices.
- Python's enumerate wraps an iterator to yield running count pairs with an optional start.
- Composing enumerate(zip(...)) unpacks rank alongside paired data in one expressive step.
- A trailing 'if' in Python comprehensions filters elements before evaluating the output expression.
- Braces with a colon produce a dict comprehension, while braces with single values build a set.
- Comprehensions eliminate manual boilerplate like instantiating empty collections and appending.
- Parentheses create a generator expression that yields items on demand instead of in memory.
- Brackets create a list comprehension that allocates the entire sequence in RAM up front.
- Passing a generator expression directly into a consumer function avoids intermediate list storage.
- Python's match statement unpacks nested dicts and lists without manual key index checks.
- The star prefix (*rest) in sequence patterns captures arbitrarily sized remaining slices.
- Guard clauses with 'if' add dynamic predicates after a structural shape match succeeds.
- Python's collections.Counter defaults missing keys to zero and supports running tallies.
- Python's collections.defaultdict invokes a factory callable automatically for unseen keys.
- Specialized collections remove repetitive key presence inspection before updates.
- Python evaluates default argument expressions once when the def statement executes, not on each call
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Writing Idiomatic Python the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
You want to print numbered steps starting at 1 instead of 0. How does enumerate handle this?
Get it right to open this lesson and 9 more in the app.
How to learn Writing Idiomatic Python, step by step
Go in order. 10 short levels across 2 sections, about 20 minutes in all, five minutes a day.
- 1
Expressive Control and Functions
- Expressive Iteration and Collections
- Function Ergonomics and Scope
- 2
Resource Management and the Object Model
- Context Managers and Resource Safety
- Leveraging the Python Data Model
2 sections · 4 units · 10 levels. Built to play, not to enroll.
Questions about Writing Idiomatic Python
How do I learn Writing Idiomatic Python?
Go in order: start with Expressive Control and Functions, then Resource Management and the Object Model. On Tomo that's 10 short levels, about 20 minutes in all, played five minutes a day. Start free and play the first level in under a minute.
Is there a Duolingo-style app for Writing Idiomatic Python?
Yes. Tomo works like Duolingo: short daily lessons, streaks and quick quizzes. Writing Idiomatic Python is one of its free courses, and you can type any other topic to get a course of your own.
Is the Writing Idiomatic Python course free?
Yes. Writing Idiomatic Python is playable on Tomo's free plan, which doesn't expire. No credit card, no waitlist. Download the app and start your first lesson.
How long does it take to learn Writing Idiomatic Python?
10 levels across 2 sections, about 20 minutes of play in total. It's built for five minutes a day, so you finish it a little at a time instead of all at once.
Do I need any background to start Writing Idiomatic Python?
No. It's pitched at an intermediate level, so it starts where you are and builds up. If you can tap a phone, you can start.
Tomo is in ChatGPT
Tomo is also a ChatGPT plugin: the same playable courses, built and played inside your chat.
Add Tomo to ChatGPT- What to ask
- “Make me a Tomo course on black holes.” “Turn this chat into a Tomo course.”
- What you get
- Quick questions with instant feedback, hearts and stars, ready to play in about a minute.
- Where it goes
- No sign-up to start. Connect your Tomo account and your streak carries on in the app.
You pick the voice
Writing Idiomatic Python is taught in the Professor style: clear, structured, thorough. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start Writing Idiomatic Python today.
Download Tomo, search Writing Idiomatic Python, and play your first lesson in under a minute.