pyproject.tomlsetup.py based project?This section covers the basics of how to install Pythonpackages.
It’s important to note that the term “package” in this context is being used todescribe a bundle of software to be installed (i.e. as a synonym for adistribution). It does not refer to the kindofpackage that you import in your Python source code(i.e. a container of modules). It is common in the Python community to refer toadistribution using the term “package”. Usingthe term “distribution” is often not preferred, because it can easily beconfused with a Linux distribution, or another larger software distributionlike Python itself.
This section describes the steps to follow before installing other Pythonpackages.
Before you go any further, make sure you have Python and that the expectedversion is available from your command line. You can check this by running:
python3--version
py --version
You should get some output likePython3.6.3. If you do not have Python,please install the latest 3.x version frompython.org or refer to theInstalling Python section of the Hitchhiker’s Guide to Python.
Note
If you’re a newcomer and you get an error like this:
>>>python3--versionTraceback (most recent call last): File"<stdin>", line1, in<module>NameError:name 'python3' is not defined
It’s because this command and other suggested commands in this tutorialare intended to be run in ashell (also called aterminal orconsole). See the Python for Beginnersgetting started tutorial foran introduction to using your operating system’s shell and interacting withPython.
Note
If you’re using an enhanced shell like IPython or the Jupyternotebook, you can run system commands like those in this tutorial byprefacing them with a! character:
In [1]: import sys !{sys.executable} --versionPython 3.6.3It’s recommended to write{sys.executable} rather than plainpython inorder to ensure that commands are run in the Python installation matchingthe currently running notebook (which may not be the same Pythoninstallation that thepython command refers to).
Note
Due to the way most Linux distributions are handling the Python 3migration, Linux users using the system Python without creating a virtualenvironment first should replace thepython command in this tutorialwithpython3 and thepython-mpip command withpython3-mpip--user. Donotrun any of the commands in this tutorial withsudo: if you get apermissions error, come back to the section on creating virtual environments,set one up, and then continue with the tutorial as written.
Additionally, you’ll need to make sure you havepip available. You cancheck this by running:
python3-mpip--version
py -m pip --version
If you installed Python from source, with an installer frompython.org, orviaHomebrew you should already have pip. If you’re on Linux and installedusing your OS package manager, you may have to install pip separately, seeInstalling pip/setuptools/wheel with Linux Package Managers.
Ifpip isn’t already installed, then first try to bootstrap it from thestandard library:
python3-mensurepip--default-pip
py -m ensurepip --default-pip
If that still doesn’t allow you to runpython-mpip:
Securely Downloadget-pip.py[1]
Runpythonget-pip.py.[2] This will install or upgrade pip.Additionally, it will installSetuptools andwheel if they’renot installed already.
Warning
Be cautious if you’re using a Python install that’s managed by youroperating system or another package manager. get-pip.py does notcoordinate with those tools, and may leave your system in aninconsistent state. You can usepythonget-pip.py--prefix=/usr/local/to install in/usr/local which is designed for locally-installedsoftware.
Whilepip alone is sufficient to install from pre-built binary archives,up to date copies of thesetuptools andwheel projects are usefulto ensure you can also install from source archives:
python3-mpipinstall--upgradepipsetuptoolswheel
py -m pip install --upgrade pip setuptools wheel
Seesection below for details,but here’s the basicvenv[3] command to use on a typical Linux system:
python3-mvenvtutorial_envsourcetutorial_env/bin/activatepy -m venv tutorial_envtutorial_env\Scripts\activate
This will create a new virtual environment in thetutorial_env subdirectory,and configure the current shell to use it as the defaultpython environment.
Python “Virtual Environments” allow Pythonpackages to be installed in an isolated location for a particular application,rather than being installed globally. If you are looking to safely installglobal command line tools,seeInstalling stand alone command line tools.
Imagine you have an application that needs version 1 of LibFoo, but anotherapplication requires version 2. How can you use both these applications? If youinstall everything into /usr/lib/python3.6/site-packages (or whatever yourplatform’s standard location is), it’s easy to end up in a situation where youunintentionally upgrade an application that shouldn’t be upgraded.
Or more generally, what if you want to install an application and leave it be?If an application works, any change in its libraries or the versions of thoselibraries can break the application.
Also, what if you can’t installpackages into theglobal site-packages directory? For instance, on a shared host.
In all these cases, virtual environments can help you. They have their owninstallation directories and they don’t share libraries with other virtualenvironments.
Currently, there are two common tools for creating Python virtual environments:
venv is available by default in Python 3.3 and later, and installspip into created virtual environments in Python 3.4 and later(Python versions prior to 3.12 also installedSetuptools).
virtualenv needs to be installed separately, but supports Python 2.7+and Python 3.3+, andpip,Setuptools andwheel areinstalled into created virtual environments by default. Note thatsetuptools is no longerincluded by default starting with Python 3.12 (andvirtualenv follows this behavior).
The basic usage is like so:
Usingvenv:
python3-mvenv<DIR>source<DIR>/bin/activatepy -m venv<DIR><DIR>\Scripts\activate
Usingvirtualenv:
python3-mvirtualenv<DIR>source<DIR>/bin/activatevirtualenv<DIR><DIR>\Scripts\activate
For more information, see thevenv docs orthevirtualenv docs.
The use ofsource under Unix shells ensuresthat the virtual environment’s variables are set within the currentshell, and not in a subprocess (which then disappears, having nouseful effect).
In both of the above cases, Windows users shouldnot use thesource command, but should rather run theactivatescript directly from the command shell like so:
<DIR>\Scripts\activate
Managing multiple virtual environments directly can become tedious, so thedependency management tutorial introduces ahigher level tool,Pipenv, that automatically manages a separatevirtual environment for each project and application that you work on.
pip is the recommended installer. Below, we’ll cover the most commonusage scenarios. For more detail, see thepip docs,which includes a completeReference Guide.
The most common usage ofpip is to install from thePython PackageIndex using arequirement specifier. Generally speaking, a requirement specifier iscomposed of a project name followed by an optionalversion specifier. A full description of the supported specifiers can befound in theVersion specifier specification.Below are some examples.
To install the latest version of “SomeProject”:
python3-mpipinstall"SomeProject"py -m pip install"SomeProject"To install a specific version:
python3-mpipinstall"SomeProject==1.4"py -m pip install"SomeProject==1.4"To install greater than or equal to one version and less than another:
python3-mpipinstall"SomeProject>=1,<2"py -m pip install"SomeProject>=1,<2"To install a version that’scompatiblewith a certain version:[4]
python3-mpipinstall"SomeProject~=1.4.2"py -m pip install"SomeProject~=1.4.2"In this case, this means to install any version “==1.4.*” version that’s also“>=1.4.2”.
pip can install from eitherSource Distributions (sdist) orWheels, but if both are presenton PyPI, pip will prefer a compatiblewheel. You can overridepip`s default behavior by e.g. using its–no-binary option.
Wheels are a pre-builtdistribution format that provides faster installation compared toSourceDistributions (sdist), especially when aproject contains compiled extensions.
Ifpip does not find a wheel to install, it will locally build a wheeland cache it for future installs, instead of rebuilding the source distributionin the future.
Upgrade an already installedSomeProject to the latest from PyPI.
python3-mpipinstall--upgradeSomeProject
py -m pip install --upgrade SomeProject
To installpackages that are isolated to thecurrent user, use the--user flag:
python3-mpipinstall--userSomeProject
py -m pip install --user SomeProject
For more information see theUser Installs sectionfrom the pip docs.
Note that the--user flag has no effect when inside a virtual environment- all installation commands will affect the virtual environment.
IfSomeProject defines any command-line scripts or console entry points,--user will cause them to be installed inside theuser base’s binarydirectory, which may or may not already be present in your shell’sPATH. (Starting in version 10, pip displays a warning wheninstalling any scripts to a directory outsidePATH.) If the scriptsare not available in your shell after installation, you’ll need to add thedirectory to yourPATH:
On Linux and macOS you can find the user base binary directory by runningpython-msite--user-base and addingbin to the end. For example,this will typically print~/.local (with~ expanded to the absolutepath to your home directory) so you’ll need to add~/.local/bin to yourPATH. You can set yourPATH permanently bymodifying ~/.profile.
On Windows you can find the user base binary directory by runningpy-msite--user-site and replacingsite-packages withScripts. Forexample, this could returnC:\Users\Username\AppData\Roaming\Python36\site-packages so you wouldneed to set yourPATH to includeC:\Users\Username\AppData\Roaming\Python36\Scripts. You can set your userPATH permanently in theControl Panel. You may need to log out for thePATH changes to take effect.
Install a list of requirements specified in aRequirements File.
python3-mpipinstall-rrequirements.txt
py -m pip install -r requirements.txt
Install a project from VCS in “editable” mode. For a full breakdown of thesyntax, see pip’s section onVCS Support.
python3-mpipinstall-eSomeProject@git+https://git.repo/some_pkg.git# from gitpython3-mpipinstall-eSomeProject@hg+https://hg.repo/some_pkg# from mercurialpython3-mpipinstall-eSomeProject@svn+svn://svn.repo/some_pkg/trunk/# from svnpython3-mpipinstall-eSomeProject@git+https://git.repo/some_pkg.git@feature# from a branch
py -m pip install -e SomeProject @ git+https://git.repo/some_pkg.git # from gitpy -m pip install -e SomeProject @ hg+https://hg.repo/some_pkg # from mercurialpy -m pip install -e SomeProject @ svn+svn://svn.repo/some_pkg/trunk/ # from svnpy -m pip install -e SomeProject @ git+https://git.repo/some_pkg.git@feature # from a branch
Install from an alternate index
python3-mpipinstall--index-urlhttp://my.package.repo/simple/SomeProject
py -m pip install --index-url http://my.package.repo/simple/ SomeProject
Search an additional index during install, in addition toPyPI
python3-mpipinstall--extra-index-urlhttp://my.package.repo/simpleSomeProject
py -m pip install --extra-index-url http://my.package.repo/simple SomeProject
Installing from local src inDevelopment Mode,i.e. in such a way that the project appears to be installed, but yet isstill editable from the src tree.
python3-mpipinstall-e<path>
py -m pip install -e<path>You can also install normally from src
python3-mpipinstall<path>
py -m pip install<path>Install a particular source archive file.
python3-mpipinstall./downloads/SomeProject-1.0.4.tar.gz
py -m pip install ./downloads/SomeProject-1.0.4.tar.gz
Install from a local directory containing archives (and don’t checkPyPI)
python3-mpipinstall--no-index--find-links=file:///local/dir/SomeProjectpython3-mpipinstall--no-index--find-links=/local/dir/SomeProjectpython3-mpipinstall--no-index--find-links=relative/dir/SomeProject
py -m pip install --no-index --find-links=file:///local/dir/ SomeProjectpy -m pip install --no-index --find-links=/local/dir/ SomeProjectpy -m pip install --no-index --find-links=relative/dir/ SomeProject
To install from other data sources (for example Amazon S3 storage)you can create a helper application that presents the datain a format compliant with thesimple repository API:,and use the--extra-index-url flag to direct pip to use that index.
./s3helper--port=7777python-mpipinstall--extra-index-urlhttp://localhost:7777SomeProject
Find pre-release and development versions, in addition to stable versions. Bydefault, pip only finds stable versions.
python3-mpipinstall--preSomeProject
py -m pip install --pre SomeProject
Extras are optional “variants” of a package, which may includeadditional dependencies, and thereby enable additional functionalityfrom the package. If you wish to install an extra for a package whichyou know publishes one, you can include it in the pip installation command:
python3-mpipinstall'SomePackage[PDF]'python3-mpipinstall'SomePackage[PDF]==3.0'python3-mpipinstall-e'.[PDF]'# editable project in current directory
py -m pip install"SomePackage[PDF]"py -m pip install"SomePackage[PDF]==3.0"py -m pip install -e".[PDF]" # editable project in current directory
“Secure” in this context means using a modern browser or atool likecurl that verifies SSL certificates whendownloading from https URLs.
[2]Depending on your platform, this may require root or Administratoraccess.pip is currently considering changing this bymaking userinstalls the default behavior.
[3]Beginning with Python 3.4,venv (a stdlib alternative tovirtualenv) will create virtualenv environments withpippre-installed, thereby making it an equal alternative tovirtualenv.
The compatible release specifier was accepted inPEP 440and support was released inSetuptools v8.0 andpip v6.0