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The Friday Loop

Every Friday, you'll get a recap of the most important and exciting Python and coding news. The Friday Loop also keeps everyone posted on new ArjanCodes courses and any limited offers coming up.

Featured Post

This Is How Marie Kondo Sets up Her Pytest | Issue #45

Hi there, Be honest—how much do you enjoy writing tests? If the answer is “not at all,” chances are your setup is too complicated. In this week’s video, I show you how to set up pytest the right way—step by step, with zero fluff. I go from zero tests to a fully working pytest setup, covering advanced tricks along the way (including one almost nobody knows about). 🧪 By the end, your tests will be clean, fast, and easy to maintain. No more fighting with pytest configurations. If your test suite...

Hi there, If your Docker builds are taking forever, your images are probably bloated with unnecessary dependencies. In this week’s video, I break down how to optimize your Dockerfiles step by step. 🐋 I cover better base images, BuildKit, multi-stage builds, and smarter dependency management—all to make your builds faster and leaner. Plus, I ran into a weird Docker issue I still haven’t figured out. Watch today’s video and speed up your builds! 🎥 Cheers, Arjan # News Happy Pi Day! 🐍🥧 Besides...

Hi there, Did you know Python has over 60 built-in functions, and you can use them without importing a single module? This week I explore 12 powerful built-ins that can make your code more efficient and Pythonic. Some of these are absolute game-changers, and yet, I rarely see them used! In this video, you’ll learn how to: ✅ Use filter() and map() for cleaner data processing ✅ Pair iterables like a pro with zip() ✅ Turn any function into an iterator with iter(callable, sentinel) (yes, that’s a...

Hi there, If you’ve ever looked at TypeScript code and thought, “Hey, that kinda looks like Python!”, you’re not wrong. But under the hood, these two languages couldn’t be more different. Python was designed for simplicity and readability. It’s dynamically typed, making development easy but deployment tricky. TypeScript, on the other hand, adds strict static typing to JavaScript, helping with large-scale applications but making setup and debugging more complex. So, which one should you use? 🤔...

Hi there, You use Python every day, but have you ever wondered how new features make it into the language? It all starts with a PEP—a Python Enhancement Proposal. Some PEPs go unnoticed, but others, like PEP 484, changed the language forever. It introduced type hints, and let’s just say… not everyone was happy about it. In this week’s video, I take a deep dive into: ✅ The PEP process—who decides Python’s future? ✅ Why type hints caused such a stir in the community ✅ The fascinating...

Hi there, Python is simple but frustrating. Rust is powerful but strict. And then there’s Go—fast, modern, and surprisingly easy to use. I put it to the test against Python and Rust, and what I found blew my mind. 🤯 Go nails concurrency, has built-in tools (no pytest or flake8 needed), and in some cases… it even beats Rust in performance. Yes, really. I built a REST API, ran benchmarks, and compared everything from syntax to error handling. Is Go the perfect balance between Python’s...

Hi there, Ever wish you could combine the simplicity of SQL with the flexibility of DataFrames? Meet DuckDB—a tiny, analytics-focused database that works wonders for anyone wrangling data. 🦆✨ In this week’s video, I explore: Why DuckDB is perfect for analytical workloads How it seamlessly integrates with tools like Pandas The difference between in-memory and persistent storage If you’re tired of clunky workflows and want a lightweight, powerful solution, this is a tool you need to see in...

Hi there, You've certainly read all about the new AI model from China, DeepSeek, and how its release affected the stock market. To be honest though, I don't believe it will affect us software developers all that much (we're all pretty much screwed anyway 🙄). In today's video I briefly share my thoughts about DeepSeek and other recent AI models, and what you should do to navigate all these changes and benefit from them as a software engineer. Wish you a great weekend! Cheers, Arjan # News Is...

Hi there, Let’s talk about Python—the language we all love. ❤️ You might think you know your way around it, but even senior developers can fall into common traps or miss out on some of its best features. In this week’s video, I break down 10 tips that will make your code cleaner, faster, and more Pythonic. For example, comprehensions are not just for lists—you can use them for sets, dictionaries, and even generators. And if you’re not using f-strings yet… well, you’re missing out on a lot of...

Hi there, Honey might save you a few bucks, but it’s stealing from creators while doing so. Ouch. 🍯 In this week’s video, I tackle this issue head-on by designing a less evil version of Honey: meet Kale. 🥬 Kale is a browser extension that’s transparent, open-source, and creator-friendly. It doesn’t override affiliate cookies, gives users control, and still applies sweet discount coupons. But this video isn’t just about the what—it’s also about the how. I break down the full architecture, the...