~pycoders | Issue #683: Narwhals, ty, LangChain, and More (May 27, 2025) (26)

Narwhals: Unified DataFrame Functions Narwhals is a lightweight compatibility layer between DataFrame libraries. You can use it as a common interface to write reproducible and maintainable data science code which supports pandas, Polars, DuckDB, PySpark, PyArrow, and more CODECUT.AI • Shared by Marco Gorelli

ty: Astral’s New Type Checker (Formerly Red-Knot) The folks over at Astral are back with another amazing project: ty, formerly known as Red-Knot, it is a new type checker. Talk Python interviews Charlie Marsh and Carl Meyer about this new tool. KENNEDY ET AL podcast

First Steps With LangChain Large language models (LLMs) have taken the world by storm. In this step-by-step video course, you’ll learn to use the LangChain library to build LLM-assisted applications. REAL PYTHON course

Understanding Random Forest Using Python A Random Forest is a powerful machine learning algorithm that can be used for classification and regression, is interpretable, and doesn’t require feature scaling. Here’s how to apply it with scikit-learn. MICHAEL GALARNYK • Shared by Michael Galarnyk

Understanding Python Web Deployment Trying to deploy server-side Python web applications may be overwhelming. This tutorial breaks down the why of things, rather than the what, and makes recommendations on how to approach the problem. MIREK DŁUGOSZ

Meta Announces Pyrefly Pyrefly is an open souce Python type checker and IDE extension built in Rust. This post announces its availability, tells you why they built it, and how you can use it. META

How to Group Data Using Polars .group_by() Start using Polars .group_by() to make sense of your data. This tutorial shows you how to group, aggregate, and reveal hidden insights with hands-on examples. REAL PYTHON

Nested Loops in Python Learn how to use nested loops in Python to iterate over multiple sequences and perform repeated actions efficiently in your programs. REAL PYTHON

Machine Learning With DuckDB and scikit-learn Learn how to prototype a machine learning workflow using DuckDB for data handling and scikit-learn for modeling. PETRICA LEUCA

Python: The Documentary There’s a new documentary in the works on Python and its popularity. This is the official trailer. YOUTUBE.COM video

The Guide to Hashing I Wish I Had When I Started Learn the basics of hashing in this beginner-friendly guide. Discover what hashing is, how it works, its key principles, common algorithms, and practical uses for password storage and file integrity. (Code examples aren’t in Python, but most of the explanation is in text). ANTON ÖDMAN

Loading Pydantic Models From JSON Pydantic’s JSON loading uses a huge amount of memory; here’s how to reduce it. ITAMAR TURNER-TRAURING