Install packages in a virtual environment using pip and venv (2024)

Create a new virtual environment#

venv (for Python 3) allows you to manage separate package installations fordifferent projects. It creates a “virtual” isolated Python installation. Whenyou switch projects, you can create a new virtual environment which is isolatedfrom other virtual environments. You benefit from the virtual environmentsince packages can be installed confidently and will not interfere withanother project’s environment.

To create a virtual environment, go to your project’s directory and run thefollowing command. This will create a new virtual environment in a local foldernamed .venv:

python3 -m venv .venv

py -m venv .venv

The second argument is the location to create the virtual environment. Generally, youcan just create this in your project and call it .venv.

venv will create a virtual Python installation in the .venv folder.

Activate a virtual environment#

Before you can start installing or using packages in your virtual environment you’llneed to activate it. Activating a virtual environment will put thevirtual environment-specific python and pip executables into yourshell’s PATH.

source .venv/bin/activate

.venv\Scripts\activate

To confirm the virtual environment is activated, check the location of yourPython interpreter:

which python

where python

While the virtual environment is active, the above command will output afilepath that includes the .venv directory, by ending with the following:

.venv/bin/python

.venv\Scripts\python

While a virtual environment is activated, pip will install packages into thatspecific environment. This enables you to import and use packages in yourPython application.

Deactivate a virtual environment#

If you want to switch projects or leave your virtual environment,deactivate the environment:

deactivate

Reactivate a virtual environment#

If you want to reactivate an existing virtual environment, follow the sameinstructions about activating a virtual environment. There’s no need to createa new virtual environment.

Install a package#

For example,let’s install theRequests library from the Python Package Index (PyPI):

python3 -m pip install requests

py -m pip install requests

pip should download requests and all of its dependencies and install them:

Collecting requests Using cached requests-2.18.4-py2.py3-none-any.whlCollecting chardet<3.1.0,>=3.0.2 (from requests) Using cached chardet-3.0.4-py2.py3-none-any.whlCollecting urllib3<1.23,>=1.21.1 (from requests) Using cached urllib3-1.22-py2.py3-none-any.whlCollecting certifi>=2017.4.17 (from requests) Using cached certifi-2017.7.27.1-py2.py3-none-any.whlCollecting idna<2.7,>=2.5 (from requests) Using cached idna-2.6-py2.py3-none-any.whlInstalling collected packages: chardet, urllib3, certifi, idna, requestsSuccessfully installed certifi-2017.7.27.1 chardet-3.0.4 idna-2.6 requests-2.18.4 urllib3-1.22

Install a specific package version#

pip allows you to specify which version of a package to install usingversion specifiers. For example, to installa specific version of requests:

python3 -m pip install 'requests==2.18.4'

py -m pip install "requests==2.18.4"

To install the latest 2.x release of requests:

python3 -m pip install 'requests>=2.0.0,<3.0.0'

py -m pip install "requests>=2.0.0,<3.0.0"

To install pre-release versions of packages, use the --pre flag:

python3 -m pip install --pre requests

py -m pip install --pre requests

Install extras#

Some packages have optional extras. You can tell pip to install these byspecifying the extra in brackets:

python3 -m pip install 'requests[security]'

py -m pip install "requests[security]"

Install a package from source#

pip can install a package directly from its source code. For example, to installthe source code in the google-auth directory:

cd google-authpython3 -m pip install .

cd google-authpy -m pip install .

Additionally, pip can install packages from source indevelopment mode,meaning that changes to the source directory will immediately affect theinstalled package without needing to re-install:

python3 -m pip install --editable .

py -m pip install --editable .

Install from version control systems#

pip can install packages directly from their version control system. Forexample, you can install directly from a git repository:

google-auth @ git+https://github.com/GoogleCloudPlatform/google-auth-library-python.git

For more information on supported version control systems and syntax, see pip’sdocumentation on VCS Support.

Install from local archives#

If you have a local copy of a Distribution Package’s archive (a zip,wheel, or tar file) you can install it directly with pip:

python3 -m pip install requests-2.18.4.tar.gz

py -m pip install requests-2.18.4.tar.gz

If you have a directory containing archives of multiple packages, you can tellpip to look for packages there and not to use thePython Package Index (PyPI) at all:

python3 -m pip install --no-index --find-links=/local/dir/ requests

py -m pip install --no-index --find-links=/local/dir/ requests

This is useful if you are installing packages on a system with limitedconnectivity or if you want to strictly control the origin of distributionpackages.

Install from other package indexes#

If you want to download packages from a different index than thePython Package Index (PyPI), you can use the --index-url flag:

python3 -m pip install --index-url http://index.example.com/simple/ SomeProject

py -m pip install --index-url http://index.example.com/simple/ SomeProject

If you want to allow packages from both the Python Package Index (PyPI)and a separate index, you can use the --extra-index-url flag instead:

python3 -m pip install --extra-index-url http://index.example.com/simple/ SomeProject

py -m pip install --extra-index-url http://index.example.com/simple/ SomeProject