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

Piggybacking off @stephen-j-fuhry here is a powershell equivalent I use:

pip freeze | ? { $_ -notmatch ((gc req.txt) -join "|") }