Concepts: Python Data Structures

Short essays on why Python's data structures work the way they do. These are the pieces you read once and keep coming back to when something surprises you in practice — the "ah, that's why" layer beneath the syntax.

Essays in this section

• Mutable versus immutable — why Python has both, and what the distinction means for your code.
• Hash tables and dictionaries — how dictionaries work under the hood and why keys must be hashable.
• Choosing data structures — the trade-offs between lists, tuples, dictionaries, and sets at a deeper level.
• Memory and performance — how data-structure choice affects speed and memory usage.