Python Polars: The Definitive Cheatsheet
Python Polars Cheatsheet (based on our O'Reilly book)
Polars is a fast, expressive DataFrame library for Python, offering both eager and lazy APIs. This cheatsheet, based on the O'Reilly book, covers data structures, data types, reading/writing data, and key transformations like selecting, filtering, aggregating, and reshaping. It highlights Polars' advantages over pandas, such as no row index, immutability, and an optimizer that applies predicate and projection pushdowns. Includes practical examples and tips for handling large datasets with the streaming engine.
The optimizer automatically applies predicate pushdown (filtering as early as possible) and projection pushdown (dropping columns that are never used).