Hi, I’m Thijs

A conversation about Polars’ history, performance, and the book, in Dutch.

Lazy vs eager APIs, converting from Pandas, and practical Polars tips with Jeroen Janssens and Thijs Nieuwdorp.

Live demo of Polars Cloud: distributed execution, the Query Profiler, and multi-node clusters. Hosted as a marimo livestream.

How Polars is changing Python data processing, with Jeroen Janssens and Thijs Nieuwdorp.

A conversation with Joe Reis about Polars, the evolution of the library, and the O’Reilly book.

A podcast with Jon Krohn.

What we learned by converting a large codebase from Pandas to Polars.

After almost two years of writing, Python Polars: the Definitive Guide is out. Jeroen Janssens and I started working on it in the summer of 2023, and it is now available from O’Reilly. Why we wrote it Polars was growing fast. The community was active, the library was improving quickly, and more and more teams were asking whether they should switch from Pandas. But there was no comprehensive resource that covered the full API, explained the design philosophy, and showed how to apply it to real problems. ...

This post was written as an experiment with ChatGPT. The benchmarks and opinions are my own; the writing style is largely AI-generated. Where Have You Been All My Life? Let me paint you a familiar picture: You’re excited to start a new Python project. You git clone that fancy repo and you have to figure out how to install the python environment on your system. It can consist of installing the right python version, picking the right dependency manager to install everything and waiting 45 minutes for everything to install, only to run into yanked versions, or incompatibilities for your specific config. Enter uv - Astral’s answer to Python tooling fatigue. ...

What we learned by converting a large codebase from Pandas to Polars.