Course

Polars for Python Developers

Build fast, reliable local data pipelines with Polars — expressions, schemas, joins, window functions, lazy execution, and a real capstone.

At a glance

Level
Beginner to Intermediate
Lessons
1 lessons across 1 module
What you build
Thistlewood Goods' local analytics pipeline, end to end
Cost
100% free · runs entirely on your own laptop, no cloud account

What you'll build

You'll work with Thistlewood Goods, a small home-goods retailer, building one real analytics pipeline that grows module by module: reading and summarizing raw CSVs, mastering Polars' expression system (the foundation everything else builds on), cleaning and validating messy real-world data, wrangling strings and categories, working with nested list and struct columns, aggregating with group_by and window functions, joining and reshaping across five real tables, analyzing time series, and finally moving from eager to lazy execution across CSV, JSON, Parquet, and SQLite. The capstone assembles all of it into one local analytics pipeline — ingest, clean, join, aggregate, and write processed output — entirely on your own machine.

Before you start

What you'll be able to do

  • Think in expressions — pl.col, select, with_columns, and filter as the core mental model
  • Clean, validate, and type-cast real messy local data
  • Aggregate with group_by, window functions, joins, and reshaping
  • Work with nested data, time series, and lazy execution across CSV, JSON, Parquet, and SQLite

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Course syllabus

Work through the modules at your own pace. Each lesson is a self-contained, hands-on read.

1 Start with a Real Workflow 1 lessons · 1–2 weeks

Before you start

You'll need basic Python — variables, functions, lists and dictionaries — and a working command line. No pandas experience is required: this course teaches Polars as its own complete tool, not a pandas port. No cloud account and no GPU are needed anywhere in this course.

Set up your environment

Everything in this course runs for real, locally, on your own machine — no cloud account, nothing to pay for.

  1. Python 3.10+ and a virtual environment — Module 1 walks through project setup from scratch.
  2. Polars — a single pip install polars, verified in Lesson 1.

Every command in every lesson is real and was actually run to produce the output you'll see — nothing is simulated or invented.

Ready to think in expressions?

Start with a real local pipeline in Lesson 1 — then build up to joins, window functions, and a full local analytics capstone.

Start the first lesson

Want this taught live to your team?

Mehdi runs tailored corporate workshops on this exact material — hands-on, in-person or remote.

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