Long long ago, beneath the eternal ice of the northern seas, there lived polar bears traveling the oceans in their mighty submarines. They were fearless explorers and skilled data scientists. The polar bears would dive into the deep waters to discover hidden worlds, collect data, to analyze and plot it, and to uncover seafood no creature had tasted before.

This is a Python tutorial featuring the polars library. It focuses on the technical basics of Data Science – working with tabular data. On the way, you will help the polar bears explore the deep sea.

Contents

• Preparations
• Read and Write Data
• Inspect DataFrames
• Select Rows and Columns
• Data Wrangling
• Data Cleaning
• High-Quality Plots
• Descriptive Statistics
• Pivot Tables
• String Handling
• Edit Columns
• Create DataFrames
• Narwhals
• Dashboard
• Links

Image Sources

Most images for this tutorial were created with the generative neural networks ChatGPT and Canva

License

© 2026 Shreyaasri Prakash and Kristian Rother

Unless stated otherwise, the content of this tutorial may be used under the conditions of the Creative Commons Attribution Share-Alike License 4.0 (CC-BY-SA 4.0). See creativecommons.org .

Acknowledgements

We would like to thank the following people for inspiring exchange on training and Python that this material has benefited from: Jasmin Touati, Veit Schiele, Dinu Gherman, Pedro Fernandes, Tomasz Puton, Edward Jenkins, Bernard Szlachta, Robert Lehmann, Allegra Via, Kaja Milanowska, Anna Philips, Paul Wlodkowski, Tom Gadsby, Stefan Roth, Gesa Johannsen, Ugur Ural, Malte Bonart, Paula Gonzalez, Samuel McGuire, Sara Maras, Carmine Somma, Kiran Challa, Dina Deifallah, Marija Vlajic, Emely Henninger and Magdalena Rother.