How can I use a pip requirements file to uninstall as well as install packages?

Question

I have a pip requirements file that changes during development.

Can pip be made to uninstall packages that do not appear in the requirement

Answer 1

It's not a feature of pip, no. If you really want such a thing, you could write a script to compare the output of pip freeze with your requirements.txt, but it would likely be more hassle than it's worth.

Using virtualenv, it is easier and more reliable to just create a clean environment and (re)install from requirements.txt, like:

deactivate
rm -rf venv/
virtualenv venv/
source venv/bin/activate
pip install -r requirements.txt