12. Virtual Environments and Packages — Python 3.13.1 documentation (../_static/pygments.css?v=b86133f3) (../_static/pydoctheme.css?v=08c2cdb3) (../_static/pygments_dark.css?v=5349f25f) (Search within Python 3.13.1 documentation) (../_static/opensearch.xml) (About these documents) (../about.html) (Index) (../genindex.html) (Search) (../search.html) (Copyright) (../copyright.html) (13. What Now?) (whatnow.html) (11. Brief Tour of the Standard Library — Part II) (stdlib2.html) (https://docs.python.org/3/tutorial/venv.html) (../_static/pydoctheme_dark.css) (../_static/py.svg)    (https://www.python.org/) (Python logo)  (3.14) dev (3.14) (3.13) 3.13.1 (3.12) 3.12 (3.11) 3.11 (3.10) 3.10 (3.9) 3.9 (3.8) 3.8 (3.7) 3.7 (3.6) 3.6 (3.5) 3.5 (3.4) 3.4 (3.3) 3.3 (3.2) 3.2 (3.1) 3.1 (3.0) 3.0 (2.7) 2.7 (2.6) 2.6     (Quick search) (Go)    (en) English (es) Spanish (fr) French (it) Italian (ja) Japanese (ko) Korean (pl) Polish (pt-br) Brazilian Portuguese (tr) Turkish (zh-cn) Simplified Chinese (zh-tw) Traditional Chinese   Theme (auto) Auto (light) Light (dark) Dark   (../contents.html) Table of Contents  12. Virtual Environments and Packages 12.1. Introduction  12.2. Creating Virtual Environments  12.3. Managing Packages with pip      Previous topic (stdlib2.html) (previous chapter) 11.  Brief Tour of the Standard Library — Part II   Next topic (whatnow.html) (next chapter) 13.  What Now?   This Page (../bugs.html) Report a Bug  (https://github.com/python/cpython/blob/main/Doc/tutorial/venv.rst) Show Source        Navigation (../genindex.html) (General Index) index  (../py-modindex.html) (Python Module Index) modules | (whatnow.html) (13. What Now?) next | (stdlib2.html) (11. Brief Tour of the Standard Library — Part II) previous | (Python logo)  (https://www.python.org/) Python » (en) English (es) Spanish (fr) French (it) Italian (ja) Japanese (ko) Korean (pl) Polish (pt-br) Brazilian Portuguese (tr) Turkish (zh-cn) Simplified Chinese (zh-tw) Traditional Chinese   (3.14) dev (3.14) (3.13) 3.13.1 (3.12) 3.12 (3.11) 3.11 (3.10) 3.10 (3.9) 3.9 (3.8) 3.8 (3.7) 3.7 (3.6) 3.6 (3.5) 3.5 (3.4) 3.4 (3.3) 3.3 (3.2) 3.2 (3.1) 3.1 (3.0) 3.0 (2.7) 2.7 (2.6) 2.6     (../index.html) 3.13.1 Documentation »  (index.html) The Python Tutorial » () 12.  Virtual Environments and Packages  (Quick search) (Go)   |  Theme (auto) Auto (light) Light (dark) Dark   |    12.  Virtual Environments and Packages(Link to this heading) ¶  12.1.  Introduction(Link to this heading) ¶  Python applications will often use packages and modules that don’t
come as part of the standard library.  Applications will sometimes
need a specific version of a library, because the application may
require that a particular bug has been fixed or the application may be
written using an obsolete version of the library’s interface. This means it may not be possible for one Python installation to meet
the requirements of every application.  If application A needs version
1.0 of a particular module but application B needs version 2.0, then
the requirements are in conflict and installing either version 1.0 or 2.0
will leave one application unable to run. The solution for this problem is to create a (../glossary.html#term-virtual-environment) virtual environment  , a
self-contained directory tree that contains a Python installation for a
particular version of Python, plus a number of additional packages. Different applications can then use different virtual environments.
To resolve the earlier example of conflicting requirements,
application A can have its own virtual environment with version 1.0
installed while application B has another virtual environment with version 2.0.
If application B requires a library be upgraded to version 3.0, this will
not affect application A’s environment.  12.2.  Creating Virtual Environments(Link to this heading) ¶  The module used to create and manage virtual environments is called (../library/venv.html#module-venv) (venv: Creation of virtual environments.) venv   . (../library/venv.html#module-venv) (venv: Creation of virtual environments.) venv   will install the Python version from which
the command was run (as reported by the (../using/cmdline.html#cmdoption-version) --version   option).
For instance, executing the command with python3.12  will install
version 3.12. To create a virtual environment, decide upon a directory where you want to
place it, and run the (../library/venv.html#module-venv) (venv: Creation of virtual environments.) venv   module as a script with the directory path:  python - m venv tutorial - env    This will create the tutorial-env  directory if it doesn’t exist,
and also create directories inside it containing a copy of the Python
interpreter and various supporting files. A common directory location for a virtual environment is .venv  .
This name keeps the directory typically hidden in your shell and thus
out of the way while giving it a name that explains why the directory
exists. It also prevents clashing with .env  environment variable
definition files that some tooling supports. Once you’ve created a virtual environment, you may activate it. On Windows, run:  tutorial - env \Scripts \activate    On Unix or MacOS, run:  source tutorial - env / bin / activate    (This script is written for the bash shell.  If you use the csh or fish shells, there are alternate activate.csh  and activate.fish  scripts you should use
instead.) Activating the virtual environment will change your shell’s prompt to show what
virtual environment you’re using, and modify the environment so that running python  will get you that particular version and installation of Python.
For example:  $ source  ~/envs/tutorial-env/bin/activate ( tutorial-env)  $ python
Python 3 .5.1 ( default, May 6  2016 , 10 :59:36)  ...
>>> import sys
>>> sys.path [ '' , '/usr/local/lib/python35.zip' , ..., '~/envs/tutorial-env/lib/python3.5/site-packages' ] >>>    To deactivate a virtual environment, type:  deactivate    into the terminal.  12.3.  Managing Packages with pip(Link to this heading) ¶  You can install, upgrade, and remove packages using a program called pip .  By default pip  will install packages from the (https://pypi.org) Python
Package Index .  You can browse the Python
Package Index by going to it in your web browser. pip  has a number of subcommands: “install”, “uninstall”,
“freeze”, etc.  (Consult the (../installing/index.html#installing-index) Installing Python Modules  guide for
complete documentation for pip  .) You can install the latest version of a package by specifying a package’s name:  ( tutorial-env)  $ python -m pip install novas
Collecting novas  Downloading novas-3.1.1.3.tar.gz ( 136kB) Installing collected packages: novas  Running setup.py install for  novas
Successfully installed novas-3.1.1.3    You can also install a specific version of a package by giving the
package name  followed by ==  and the version number:  ( tutorial-env)  $ python -m pip install requests == 2 .6.0
Collecting requests == 2 .6.0  Using cached requests-2.6.0-py2.py3-none-any.whl
Installing collected packages: requests
Successfully installed requests-2.6.0    If you re-run this command, pip  will notice that the requested
version is already installed and do nothing.  You can supply a
different version number to get that version, or you can run python -m pip install --upgrade  to upgrade the package to the latest version:  ( tutorial-env)  $ python -m pip install --upgrade requests
Collecting requests
Installing collected packages: requests  Found existing installation: requests 2 .6.0  Uninstalling requests-2.6.0:  Successfully uninstalled requests-2.6.0
Successfully installed requests-2.7.0    python -m pip uninstall  followed by one or more package names will
remove the packages from the virtual environment. python -m pip show  will display information about a particular package:  ( tutorial-env)  $ python -m pip show requests
---
Metadata-Version: 2 .0
Name: requests
Version: 2 .7.0
Summary: Python HTTP for  Humans.
Home-page: http://python-requests.org
Author: Kenneth Reitz
Author-email: me@kennethreitz.com
License: Apache 2 .0
Location: /Users/akuchling/envs/tutorial-env/lib/python3.4/site-packages
Requires:    python -m pip list  will display all of the packages installed in
the virtual environment:  ( tutorial-env)  $ python -m pip list
novas ( 3 .1.1.3) numpy ( 1 .9.2) pip ( 7 .0.3) requests ( 2 .7.0) setuptools ( 16 .0)    python -m pip freeze  will produce a similar list of the installed packages,
but the output uses the format that python -m pip install  expects.
A common convention is to put this list in a requirements.txt  file:  ( tutorial-env)  $ python -m pip freeze > requirements.txt ( tutorial-env)  $ cat requirements.txt novas == 3 .1.1.3 numpy == 1 .9.2 requests == 2 .7.0    The requirements.txt  can then be committed to version control and
shipped as part of an application.  Users can then install all the
necessary packages with install -r  :  ( tutorial-env)  $ python -m pip install -r requirements.txt
Collecting novas == 3 .1.1.3 ( from -r requirements.txt ( line 1 ))  ...
Collecting numpy == 1 .9.2 ( from -r requirements.txt ( line 2 ))  ...
Collecting requests == 2 .7.0 ( from -r requirements.txt ( line 3 ))  ...
Installing collected packages: novas, numpy, requests  Running setup.py install for  novas
Successfully installed novas-3.1.1.3 numpy-1.9.2 requests-2.7.0    pip  has many more options.  Consult the (../installing/index.html#installing-index) Installing Python Modules  guide for complete documentation for pip  .  When you’ve written
a package and want to make it available on the Python Package Index,
consult the (https://packaging.python.org/en/latest/tutorials/packaging-projects/) Python packaging user guide .       (../contents.html) Table of Contents  12. Virtual Environments and Packages 12.1. Introduction  12.2. Creating Virtual Environments  12.3. Managing Packages with pip      Previous topic (stdlib2.html) (previous chapter) 11.  Brief Tour of the Standard Library — Part II   Next topic (whatnow.html) (next chapter) 13.  What Now?   This Page (../bugs.html) Report a Bug  (https://github.com/python/cpython/blob/main/Doc/tutorial/venv.rst) Show Source      (Collapse sidebar) «     Navigation (../genindex.html) (General Index) index  (../py-modindex.html) (Python Module Index) modules | (whatnow.html) (13. What Now?) next | (stdlib2.html) (11. Brief Tour of the Standard Library — Part II) previous | (Python logo)  (https://www.python.org/) Python » (en) English (es) Spanish (fr) French (it) Italian (ja) Japanese (ko) Korean (pl) Polish (pt-br) Brazilian Portuguese (tr) Turkish (zh-cn) Simplified Chinese (zh-tw) Traditional Chinese   (3.14) dev (3.14) (3.13) 3.13.1 (3.12) 3.12 (3.11) 3.11 (3.10) 3.10 (3.9) 3.9 (3.8) 3.8 (3.7) 3.7 (3.6) 3.6 (3.5) 3.5 (3.4) 3.4 (3.3) 3.3 (3.2) 3.2 (3.1) 3.1 (3.0) 3.0 (2.7) 2.7 (2.6) 2.6     (../index.html) 3.13.1 Documentation »  (index.html) The Python Tutorial » () 12.  Virtual Environments and Packages  (Quick search) (Go)   |  Theme (auto) Auto (light) Light (dark) Dark   |   © (../copyright.html) Copyright  2001-2025, Python Software Foundation. This page is licensed under the Python Software Foundation License Version 2. Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License. See (/license.html) History and License for more information.The Python Software Foundation is a non-profit corporation. (https://www.python.org/psf/donations/) Please donate. Last updated on Jan 09, 2025 (10:20 UTC). (/bugs.html) Found a bug ? Created using (https://www.sphinx-doc.org/) Sphinx 8.1.3.