Python
Python Packaging #5 Dependency Locking: Lock Files and Reproducibility
Starting from why declaration and lock are separate, we read the contents of uv.lock directly: the resolution result that pins every transitive dependency, the supply-chain risks hash verification blocks, reproducing the lock exactly in CI with --frozen, a strategy that turns upgrades into routine work, and pylock.toml (PEP 751), the standard that opens movement between tools.
Python Packaging #4 uv: The Standard Workflow of 2026
The daily uv workflow that folds virtual environments, dependency installation, locking, and Python version management into one tool: how init, add, sync, and run replace the manual work of earlier posts, uv installing Python interpreters themselves, isolated global tools via uvx and uv tool, and migrating existing requirements.txt projects.
Python Packaging #3 pyproject.toml: The Standard for Project Configuration
How the era of setup.py and scattered config files converged into the single pyproject.toml: metadata and dependency declarations in the project table, separating optional features and dev tooling with extras and dependency-groups, the role of build-system, and the practical layout that gathers ruff and pytest settings under the tool table.
Python Packaging #2 pip and requirements.txt: The Limits of the Traditional Workflow
How pip works and the requirements.txt workflow — and where the approach falls apart. Reading version specifiers, pip freeze's inability to distinguish direct from transitive dependencies, the reproducibility hole where unpinned installs differ by the day, and constraints files, building the case for why the next generation of tools exists.
Python Packaging #1 Virtual Environments: Why Environments Break, and venv
Starting from the structural cause of broken Python environments: the path import searches and the conflicts born from having a single site-packages, why the system Python must be left alone and what the PEP 668 error means, isolating each project with venv, and the fact that activate is nothing more than PATH manipulation.
When Your Python Server Is Slow — Finding the Bottleneck in 5 Minutes with py-spy
Using py-spy, the sampling profiler that attaches to a running Python process with no code changes or restarts: dump to identify a hung process, top for live bottleneck watching, record and flame graphs, --idle for off-CPU waits, reading the GIL numbers, and running it in containers.
Python's JIT Compiler: From the 3.13 Experiment to Realistic Expectations
A look at the experimental copy-and-patch JIT compiler that landed in CPython 3.13. How it works, how to enable it, what changed in 3.14, and what you can realistically expect from it today.
Python Without the GIL Is Here: Where Free-Threading Stands and When to Use It
The current state of free-threading, from the experimental build in Python 3.13 to official support in 3.14. Installation and verification, single-thread overhead, C extension compatibility, and the criteria for deciding whether it belongs in production today.
Python Data Analysis #7 A Taste of Polars: Your Next Move When pandas Slows Down
When pandas struggles against millions of rows, Polars is the alternative. We compare reading, filtering, and groupby side by side in pandas and Polars code, explain the idea behind lazy mode, lay out criteria for choosing between the two tools, and close out the series.
Python Data Analysis #6 Visualization: matplotlib Fundamentals and Choosing Charts
The minimal matplotlib structure understood through Figure and Axes, fast plotting with DataFrame.plot, picking the right chart for each purpose, fixing broken fonts in CJK environments, and saving with savefig — the visualization fundamentals in one post.
Python Data Analysis #5 Grouping and Joining: groupby, pivot_table, merge
Starting from the classic sales-by-branch-by-month question, we build a mental model for groupby, multi-stat aggregation with agg, pivot_table for Excel users, and merge and concat as the pandas counterparts of SQL JOIN — plus the habit of checking row counts after every join.
Python book now available free in full — Modern Python: From Basics to FastAPI in Production
From variable declarations to FastAPI, SQLAlchemy, JWT auth, and deployment, this 34-chapter, 5-part Python book is free to read in full on the site.