Install a Python package into a different directory using pip?

The --target switch is the thing you're looking for:

pip install --target=d:\somewhere\other\than\the\default package_name

But you still need to add d:\somewhere\other\than\the\default to PYTHONPATH to actually use them from that location.

-t, --target <dir>
Install packages into <dir>. By default this will not replace existing files/folders in <dir>.
Use --upgrade to replace existing packages in <dir> with new versions.

Upgrade pip if target switch is not available:

On Linux or OS X:

pip install -U pip

On Windows (this works around an issue):

python -m pip install -U pip

Use:

pip install --install-option="--prefix=$PREFIX_PATH" package_name

You might also want to use --ignore-installed to force all dependencies to be reinstalled using this new prefix. You can use --install-option to multiple times to add any of the options you can use with python setup.py install (--prefix is probably what you want, but there are a bunch more options you could use).

Instead of the --target option or the --install-options option, I have found that the following works well (from discussion on a bug regarding this very thing at https://github.com/pypa/pip/issues/446):

PYTHONUSERBASE=/path/to/install/to pip install --user

(Or set the PYTHONUSERBASE directory in your environment before running the command, using export PYTHONUSERBASE=/path/to/install/to)

This uses the very useful --user option but tells it to make the bin, lib, share and other directories you'd expect under a custom prefix rather than $HOME/.local.

Then you can add this to your PATH, PYTHONPATH and other variables as you would a normal installation directory.

Note that you may also need to specify the --upgrade and --ignore-installed options if any packages upon which this depends require newer versions to be installed in the PYTHONUSERBASE directory, to override the system-provided versions.

A full example:

PYTHONUSERBASE=/opt/mysterypackage-1.0/python-deps pip install --user --upgrade numpy scipy

..to install the scipy and numpy package most recent versions into a directory which you can then include in your PYTHONPATH like so (using bash and for python 2.6 on CentOS 6 for this example):

export PYTHONPATH=/opt/mysterypackage-1.0/python-deps/lib64/python2.6/site-packages:$PYTHONPATHexport PATH=/opt/mysterypackage-1.0/python-deps/bin:$PATH

Using virtualenv is still a better and neater solution!