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.
DeepSeek Won't Matter for Software Engineers | Issue #38
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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.
Have you ever written a Python script that felt slow, even though the logic was simple? Sometimes it’s not the efficiency of your code that's the problem, it’s when your code does its work. This week’s video is all about the Lazy Loading design pattern, and I think many developers underestimate how powerful (and practical) it is. I start with a real example: loading a huge CSV file that freezes your program for 10 seconds before doing anything useful. Then, step by step, we improve it using:...
If your code is hard to test, hard to reuse, and hard to change, you’re probably hardcoding your dependencies. It’s one of the most common architectural problems I see in Python code, even in production systems. In this week's video, I take a small but realistic example, a data pipeline that loads, transforms, and exports some records, and show you how Dependency Injection can turn it from a rigid mess into something clean, testable, and modular. No frameworks required. You’ll learn: Why...
Hi there, Most apps only store the final result: the current balance, the current inventory, the current status. But what if you could track every change that led to that result? That’s exactly what the event sourcing pattern allows you to do. Instead of overwriting state, you store a sequence of immutable events and derive the current state by replaying them. It’s like Git (kinda), but for your domain logic. In this week’s video, I show you how to implement event sourcing in Python from...