Functional Programming Will Make You a Better Python Developer

From the creator

💡 Learn how to design great software in 7 steps: https://arjan.codes/designguide. Functional programming isn't just about `map()`, `filter()`, and avoiding classes. It's a different way of thinking about how data flows through your application. In this video, I refactor a Python fraud detection system to explore pure functions, immutability, function composition, and the functional core, imperative shell pattern. You'll see how separating calculations from side effects makes your code easier to understand, test, and maintain, without having to turn Python into a purely functional language. 🔥 GitHub Repository: https://git.arjan.codes/2026/func. 💬 Join my Discord server: https://discord.arjan.codes. ⌨️ Keyboard I’m using: https://amzn.to/49YM97v. 🔖 Chapters: 0:00 Intro 1:00 Start With a Stateful Fraud Detector 1:37 1. Make the Calculations Pure 5:04 2. Think in Transformations Instead of Mutations 8:18 Function Composition 9:57 What Happens When We Add a Model? 11:05 Functional Core, Imperative Shell 13:02 Why This Still Matters When AI Writes the Code 13:51 Final Thoughts #arjancodes #softwaredesign #python

Published 2026-11-13 · Watch on YouTube ↗
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