Muhammad Almas khan’s Post

🐍 `__iter__()` & `__next__()` — How Python Loops Actually Work ******************************* Every time a `for` loop runs in Python, two methods run silently behind it. The distinction worth understanding: 1️⃣ An iterable has `__iter__()` — it can be looped over. 2️⃣ An iterator has both `__iter__()` and `__next__()` — it tracks position. Every list, string, file, and dict you loop over follows exactly this two-method protocol. ——————————————————————— When you implement it yourself, your objects become first-class citizens of the Python ecosystem — compatible with `for`, `list()`, `sum()`, `zip()`, and everything else. The real power is lazy evaluation. An iterator yields one value at a time. It does not load everything into memory upfront. That distinction becomes significant when the data is large. The visual guide below shows how both methods work, what a `for` loop actually does under the hood, and a real-world lazy CSV reader that handles large files without loading them into RAM. This series has covered `__init__()`, `__call__()`, `__enter__()` / `__exit__()`, `__del__()`, and `__str__()` / `__repr__()` — this one reveals the engine behind every loop you write. Next in the series → `__getitem__()` and `__setitem__()` Have you ever built a custom iterator? What was the use case? #Python #SoftwareEngineering #PythonDevelopment #sourcescodedev

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