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Are the SOLID principles still relevant when you’re writing Python in 2025? In this video, we take a real-world problem and implement it three ways: as a messy all-in-one script, a clean SOLID-inspired class-based version, and a lean functional approach. Along the way, we explore what each SOLID principle means in practice, when it helps, and when it actually makes things worse.
🔥 GitHub Repository: https://git.arjan.codes/2025/solid.
💡 Learn how to design great software in 7 steps: https://arjan.codes/designguide.
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⌨️ Keyboard I’m using: https://amzn.to/49YM97v.
🔖 Chapters:
0:00 Intro
0:35 The Task: Generate a Sales Report
2:37 What Is SOLID, Really?
4:32 The Messy Version (AKA reality)
7:05 The SOLID-Inspired Version (Class-Based)
16:59 The Functional Version (Same Result, Fewer Classes)
20:51 Final Thoughts
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