Eric J Ma's Website

Recently, I watched Peter Wang's PyBay talk, The Five Demons of Python Packaging That Fuel Our Persistent Nightmare, and have been reflecting on a quote from Peter's talk:

...I don't care you'll get a Python we'll get you the Python you need what's the thing you want to do

It's the difference between first worrying about "what Python do you have", instead of worrying about "what Python do you need".

uv, and in particular uvx, really adopts this paradigm. When I install a tool using uv tool or run a tool using uvx <toolname>, I can specify the exact Python interpreter version that I'd like:

uv tool install <toolname> --python <version_number>
uvx <toolname> --python <version_number> ...tool args here...

This is incredibly liberating as a user who is looking to install globally-available tools.

It's come to the point that for one-off work, I now do one of the following.

# If I'm in the mood for marimo:
uvx marimo edit --sandbox /path/to/notebook.py

# If I'm in the mood for jlab:
uvx juv run /path/to/notebook.ipynb

uvx coupled with marimo/juv and PEP723 now helps invert the process of getting started. There's no more finagling with first creating a Python environment and then getting to work. Instead, we just get to work and install packages on an as-needed basis, done on-the-fly. marimo and juv will ship you the Python that you need to do what you want to do. That's pretty rad.