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.
Coupling 101: Design Choices That Make or Break Your Code | Issue #47
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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.
Most systems don’t start out needing CQRS. They start simple: create, update, list, dashboard. Everything in one place. Everything reasonable. Until read requirements slowly begin to reshape the system, often in subtle ways 🧩. In this week’s video, I show how that happens using a FastAPI app backed by MongoDB, and how Command Query Responsibility Segregation (CQRS) provides a clean way out once reads and writes want very different things. Along the way, I cover: separating command intent from...
Code can be correct and still be unpleasant to read. A lot of software design isn’t about what the code does but about how clearly it communicates the sequence of ideas behind it. In this week’s video, I explore the Fluent Interface pattern by refactoring a small animation engine in Python. I start with a clunky but functional API, then gradually reshape it until defining an animation reads almost like a sentence: move, rotate, scale, fade. Enjoy this deep dive into API design, readability,...
Have you ever looked at a Python script and thought: “Why is this slow? The logic is trivial.” Very often, the problem isn’t what your code does, but how often it does expensive work. In this week’s video, I start with a deliberately inefficient example: parsing a large CSV file multiple times. From there, I use it as a vehicle to introduce 10 powerful Python features that many developers either don’t know about or don’t know when to apply. I look at things like: • caching expensive...