| Page Status: | Complete |
|---|---|
| Last Reviewed: | 2014-09-30 |
Contents
This tutorial covers the basics of how to install Python packages, which are known more formally as distributions.
This section describes the steps to follow before installing other Python packages. You will want to install pip and setuptools, and in most cases, virtualenv (unless you’re using pyvenv).
We recommend the following installation sequence:
Install pip and setuptools: [3]
If you have a PEP453-compliant Python 3.4, it may already have the pip command available by default (and setuptools will be installed as well), or it may at least contain a working ensurepip. To install pip (and setuptools) using ensurepip, run: python -m ensurepip --upgrade.
Otherwise:
Optionally, Create a virtual environment (See section below for details):
Using virtualenv:
pip install virtualenv
virtualenv <DIR>
source <DIR>/bin/activate
pyvenv <DIR>
source <DIR>/bin/activate
Python “Virtual Environments” allow Python distributions to be installed in an isolated location for a particular application, rather than being installed globally.
Imagine you have an application that needs version 1 of LibFoo, but another application requires version 2. How can you use both these applications? If you install everything into /usr/lib/python2.7/site-packages (or whatever your platform’s standard location is), it’s easy to end up in a situation where you unintentionally 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 those libraries can break the application.
Also, what if you can’t install distributions into the global site-packages directory? For instance, on a shared host.
In all these cases, virtual environments can help you. They have their own installation directories and they don’t share libraries with other virtual environments.
Currently, there are two viable tools for creating Python virtual environments: virtualenv and pyvenv. pyvenv is only available in Python 3.3 & 3.4, and only in Python 3.4, is pip & setuptools installed into environments by default, whereas virtualenv supports Python 2.6 thru Python 3.4 and pip & setuptools are installed by default in every version.
The basic usage is like so:
Using virtualenv:
virtualenv <DIR>
source <DIR>/bin/activate
Using pyvenv:
pyvenv <DIR>
source <DIR>/bin/activate
For more information, see the virtualenv docs or the pyvenv docs.
pip is the recommended installer, and supports various requirement forms and options. For details, see the pip docs.
Install SomeProject and its dependencies from PyPI using Requirement Specifiers
pip install SomeProject # latest version
pip install SomeProject==1.0.4 # specific version
pip install 'SomeProject>=1.0.4' # minimum version
Install a list of requirements specified in a Requirements File.
pip install -r requirements.txt
Upgrade an already installed SomeProject to the latest from PyPI.
pip install --upgrade SomeProject
Install a project from VCS in “editable” mode. For a full breakdown of the syntax, see pip’s section on VCS Support.
pip install -e git+https://git.repo/some_pkg.git#egg=SomeProject # from git
pip install -e hg+https://hg.repo/some_pkg.git#egg=SomeProject # from mercurial
pip install -e svn+svn://svn.repo/some_pkg/trunk/#egg=SomeProject # from svn
pip install -e git+https://git.repo/some_pkg.git@feature#egg=SomeProject # from a branch
Install a particular source archive file.
pip install ./downloads/SomeProject-1.0.4.tar.gz
pip install http://my.package.repo/SomeProject-1.0.4.zip
Install from an alternate index
pip install --index-url http://my.package.repo/simple/ SomeProject
Search an additional index during install, in addition to PyPI
pip install --extra-index-url http://my.package.repo/simple SomeProject
Install from a local directory containing archives (and don’t check PyPI)
pip install --no-index --find-links=file:///local/dir/ SomeProject
pip install --no-index --find-links=/local/dir/ SomeProject
pip install --no-index --find-links=relative/dir/ SomeProject
Find pre-release and development versions, in addition to stable versions. By default, pip only finds stable versions.
pip install --pre SomeProject
Wheel is a pre-built distribution format that provides faster installation compared to Source Distributions (sdist), especially when a project contains compiled extensions.
As of v1.5, pip prefers wheels over sdists when searching indexes.
Although wheels are becoming more common on PyPI, if you want all of your dependencies converted to wheel, do the following (assuming you’re using a Requirements File):
pip wheel --wheel-dir=/local/wheels -r requirements.txt
And then to install those requirements just using your local directory of wheels (and not from PyPI):
pip install --no-index --find-links=/local/wheels -r requirements.txt
Wheel is intended to replace Eggs. For a detailed comparison, see Wheel vs Egg.
To install distributions that are isolated to the current user, use the -user flag:
pip install --user SomeProject
For more information see the User Installs section from the pip docs.
| [1] | “Secure” in this context means using a modern browser or a tool like curl that verifies SSL certificates when downloading from https URLs. |
| [2] | Depending on your platform, this may require root or Administrator access. pip is currently considering changing this by making user installs the default behavior. |
| [3] | On Linux and OSX, pip and setuptools will usually be available for the system python from a system package manager (e.g. yum or apt-get for linux, or homebrew for OSX). Unfortunately, there is often delay in getting the latest version this way, so in most cases, you’ll want to use these instructions. |
| [4] | For more information on creating projects, see the Setuptools Docs |
| [5] | Beginning with Python 3.4, pyvenv (a stdlib alternative to virtualenv) will create virtualenv environments with pip pre-installed, thereby making it an equal alternative to virtualenv. |