best-practices
Data Structure Selection
Which Python data structures compile best and which to avoid.
Published May 30, 2026
Numeric Arrays: list
Use list for homogeneous numeric sequences.
Key-Value Lookups: dict
dict is highly optimised for compiled code.
Immutable Records: tuple
tuple has lower overhead than list for read-only data.
Avoid: Mixed-Type Collections
bad = [1, "two", 3.0] # boxed objectsAvoid: Nested Deep Structures
Shallow structures compile faster than deeply nested dicts of lists of dicts.