This section covers the basics of how to install Python packages.
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 kindof package that you import in your Python source code(i.e. a container of modules). It is common in the Python community to refer toa distribution 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.
Requirements for Installing Packages#
This section describes the steps to follow before installing other Pythonpackages.
Ensure you can run Python from the command line#
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 --versionpy --version
You should get some output like Python 3.6.3. If you do not have Python,please install the latest 3.x version from python.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>", line 1, 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 a shell (also called a terminal orconsole). See the Python for Beginners getting 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 plain python inorder to ensure that commands are run in the Python installation matchingthe currently running notebook (which may not be the same Pythoninstallation that the python 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 the python command in this tutorialwith python3 and the python -m pip command with python3 -m pip --user. Do notrun any of the commands in this tutorial with sudo: 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.
Ensure you can run pip from the command line#
Additionally, you’ll need to make sure you have pip available. You cancheck this by running:
python3 -m pip --version
py -m pip --version
If you installed Python from source, with an installer from python.org, orvia Homebrew 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.
If pip isn’t already installed, then first try to bootstrap it from thestandard library:
python3 -m ensurepip --default-pip
py -m ensurepip --default-pip
If that still doesn’t allow you to run python -m pip:
Securely Download get-pip.py [1]
Run
python get-pip.py. [2] This will install or upgrade pip.Additionally, it will install Setuptools and wheel 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 use
python get-pip.py --prefix=/usr/local/to install in/usr/localwhich is designed for locally-installedsoftware.
Ensure pip, setuptools, and wheel are up to date#
While pip alone is sufficient to install from pre-built binary archives,up to date copies of the setuptools and wheel projects are usefulto ensure you can also install from source archives:
python3 -m pip install --upgrade pip setuptools wheel
py -m pip install --upgrade pip setuptools wheel
Optionally, create a virtual environment#
See section below for details,but here’s the basic venv [3] command to use on a typical Linux system:
python3 -m venv tutorial_envsource tutorial_env/bin/activate
py -m venv tutorial_envtutorial_env\Scripts\activate
This will create a new virtual environment in the tutorial_env subdirectory,and configure the current shell to use it as the default python environment.
Creating Virtual Environments#
Python “Virtual Environments” allow Python packages 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,see Installing 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 install packages 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 installed Setuptools).
virtualenv needs to be installed separately, but supports Python 2.7+and Python 3.3+, and pip, Setuptools and wheel arealways installed into created virtual environments by default (regardless ofPython version).
The basic usage is like so:
Using venv:
python3 -m venv <DIR>source <DIR>/bin/activate
py -m venv <DIR><DIR>\Scripts\activate
Using virtualenv:
python3 -m virtualenv <DIR>source <DIR>/bin/activate
virtualenv <DIR><DIR>\Scripts\activate
For more information, see the venv docs orthe virtualenv docs.
The use of source 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 should not use thesource command, but should rather run the activatescript 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.
Use pip for Installing#
pip is the recommended installer. Below, we’ll cover the most commonusage scenarios. For more detail, see the pip docs,which includes a complete Reference Guide.
Installing from PyPI#
The most common usage of pip is to install from the Python PackageIndex using a requirement specifier. Generally speaking, a requirement specifier iscomposed of a project name followed by an optional version specifier. A full description of the supported specifiers can befound in the Version specifier specification.Below are some examples.
To install the latest version of “SomeProject”:
python3 -m pip install "SomeProject"
py -m pip install "SomeProject"To install a specific version:
python3 -m pip install "SomeProject==1.4"
py -m pip install "SomeProject==1.4"To install greater than or equal to one version and less than another:
python3 -m pip install "SomeProject>=1,<2"
py -m pip install "SomeProject>=1,<2"To install a version that’s compatiblewith a certain version: [4]
python3 -m pip install "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”.
Source Distributions vs Wheels#
pip can install from either Source Distributions (sdist) or Wheels, but if both are presenton PyPI, pip will prefer a compatible wheel. You can overridepip`s default behavior by e.g. using its –no-binary option.
Wheels are a pre-built distribution format that provides faster installation compared to SourceDistributions (sdist), especially when aproject contains compiled extensions.
If pip 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.
Upgrading packages#
Upgrade an already installed SomeProject to the latest from PyPI.
python3 -m pip install --upgrade SomeProject
py -m pip install --upgrade SomeProject
Installing to the User Site#
To install packages that are isolated to thecurrent user, use the --user flag:
python3 -m pip install --user SomeProject
py -m pip install --user SomeProject
For more information see the User 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.
If SomeProject defines any command-line scripts or console entry points,--user will cause them to be installed inside the user 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 outside PATH.) If the scriptsare not available in your shell after installation, you’ll need to add thedirectory to your PATH:
On Linux and macOS you can find the user base binary directory by running
python -m site --user-baseand addingbinto 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/binto yourPATH. You can set yourPATHpermanently by modifying ~/.profile.On Windows you can find the user base binary directory by running
py -msite --user-siteand replacingsite-packageswithScripts. Forexample, this could returnC:\Users\Username\AppData\Roaming\Python36\site-packagesso you wouldneed to set yourPATHto includeC:\Users\Username\AppData\Roaming\Python36\Scripts. You can set your userPATHpermanently in the Control Panel. You may need to log out for thePATHchanges to take effect.
Requirements files#
Install a list of requirements specified in a Requirements File.
python3 -m pip install -r requirements.txt
py -m pip install -r requirements.txt
Installing from VCS#
Install a project from VCS in “editable” mode. For a full breakdown of thesyntax, see pip’s section on VCS Support.
python3 -m pip install -e SomeProject @ git+https://git.repo/some_pkg.git # from gitpython3 -m pip install -e SomeProject @ hg+https://hg.repo/some_pkg # from mercurialpython3 -m pip install -e SomeProject @ svn+svn://svn.repo/some_pkg/trunk/ # from svnpython3 -m pip install -e SomeProject @ 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
Installing from other Indexes#
Install from an alternate index
python3 -m pip install --index-url http://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 to PyPI
python3 -m pip install --extra-index-url http://my.package.repo/simple SomeProject
py -m pip install --extra-index-url http://my.package.repo/simple SomeProject
Installing from a local src tree#
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 -m pip install -e <path>
py -m pip install -e <path>You can also install normally from src
python3 -m pip install <path>
py -m pip install <path>Installing from local archives#
Install a particular source archive file.
python3 -m pip install ./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 check PyPI)
python3 -m pip install --no-index --find-links=file:///local/dir/ SomeProjectpython3 -m pip install --no-index --find-links=/local/dir/ SomeProjectpython3 -m pip install --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
Installing from other sources#
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 the simple repository API:,and use the --extra-index-url flag to direct pip to use that index.
./s3helper --port=7777python -m pip install --extra-index-url http://localhost:7777 SomeProject
Installing Prereleases#
Find pre-release and development versions, in addition to stable versions. Bydefault, pip only finds stable versions.
python3 -m pip install --pre SomeProject
py -m pip install --pre SomeProject
Installing “Extras”#
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 -m pip install 'SomePackage[PDF]'python3 -m pip install 'SomePackage[PDF]==3.0'python3 -m pip install -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
