Writing Reproducible Python

  • PEP 723 allows inline metadata for Python dependencies.
  • Use uv to run single-file scripts with pure Python requirements (numpy, pandas).
  • Use Pixi when your script depends on system libraries or compiled binaries (eonclient, ffmpeg).
  • Combine them with a Pixibang (pixi exec ... -- uv run) for fully reproducible, complex scientific workflows.

Modules, Packages, and The Search Path

  • sys.path is the list of directories Python searches for imports.
  • The order of search is: Current Directory -> Standard Library -> Installed Packages.
  • A Package is a directory containing an __init__.py file.
  • Code that works locally because of the current directory will fail when shared unless properly installed.