It's a mess. On Arch Linux, we even have Python 2 and 3 side by side. While virtualenv is probably a usable solution, friends don't let friends build numpy...

I always advocate using the Anaconda Python distribution. So far, I had also advised using something like pip install --user <pkg> for packages that are not prebuilt for conda, but even that turns into a mess eventually.

It turns out there is a better way:

conda skeleton pypi <pkg>
conda build <pkg>
conda install --use-local <full pkg name>

Done! There is now a directory <pkg> containing the skeleton recipe you might want to delete.