Installing a Python package often only includes some pure Python files. If the package includes data, scripts and or executables, these are installed in different directories from the pure Python files.
Assuming your package has no data/scripts/executables, and that you want your Python files to go into
/python/packages/package_name (and not some subdirectory a few levels below
/python/packages as when using
--prefix), you can use the one time command:
pip install --install-option="--install-purelib=/python/packages" package_name
If you want all (or most) of your packages to go there, you can edit your
~/.pip/pip.conf to include:
That way you can't forget about having to specify it again and again.
Any excecutables/data/scripts included in the package will still go to their default places unless you specify addition install options (
--install-scripts, etc., for details look at the custom installation options).