Python List Behavior: Precision and Consequences

Python isn’t magical. It’s precise. And precision has consequences. Continuing my deep dive into sequences… * with lists can be a little mischievous. grid = [['_'] * 3] * 3 Looks like a clean 3×3 grid. Until you do: grid[1][2] = 'X' And suddenly every row changes. Why? Because * didn’t copy the inner list — it copied the reference to it. The safer version? grid = [['_'] * 3 for _ in range(3)] Now each row is independent. Also interesting: += on lists mutates in place. * with tuples creates a new tuple object with a separate id. And when assigning to a slice, the right side must be iterable: l[2:5] = [100] The more I explore sequences, the clearer it becomes — Still learning... #PythonLearning #BackendEngineering  #FinTechCareers

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