This section covers the basics of how to install Python packages.
To install the latest version of python 2, simply type: $ brew install python If you'd rather install the latest version of python 3, replace python with python3. There are a few package managers that are specific to Python, and pip is the preferred one. Jul 06, 2018 This short tutorial will show you how to properly install Python 3 on a Mac OS X computer. There are multiple ways to install Python 3, including a download from the official Python site, however I strongly recommend instead using a package manager like Homebrew to manage all your dependencies going forward. It will make your life a lot simpler.
It’s important to note that the term “package” in this context is being used asa synonym for a distribution (i.e. a bundle ofsoftware to be installed), not to refer to the kind of package that you import in your Python source code (i.e. a container ofmodules). It is common in the Python community to refer to a distribution using the term “package”. Using the term “distribution”is often not preferred, because it can easily be confused with a Linuxdistribution, or another larger software distribution like Python itself.
Contents
- Requirements for Installing Packages
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:
You should get some output like Python3.6.3
. 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:
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:
It’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 pip
command with pip3--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.
Additionally, you’ll need to make sure you have pip available. You cancheck this by running:
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:
If that still doesn’t allow you to run pip
:
Securely Download get-pip.py[1]
Run
pythonget-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
pythonget-pip.py--prefix=/usr/local/
to install in/usr/local
which is designed for locally-installedsoftware.
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:
See section below for details,but here’s the basic venv[3] command to use on a typical Linux system:
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.
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 and setuptools into created virtual environments inPython 3.4 and later.
- 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:
Using virtualenv:
For more information, see the venv docs or the virtualenv docs.
In both of the above cases, Windows users should _not_ use thesource command, but should rather run the activate script directlyfrom the command shell. 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).
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 the pip docs,which includes a complete Reference Guide.
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. PEP 440 contains a fullspecificationof the currently supported specifiers. Below are some examples.
To install the latest version of “SomeProject”:
To install a specific version:
To install greater than or equal to one version and less than another:
To install a version that’s “compatible”with a certain version: [4]
In this case, this means to install any version “1.4.*” version that’s also“>=1.4.2”.
pip can install from either Source Distributions (sdist) or Wheels, but if both are presenton PyPI, pip will prefer a compatible wheel.
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.
Upgrade an already installed SomeProject to the latest from PyPI.
To install packages that are isolated to thecurrent user, use the --user
flag:
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-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 by modifying ~/.profile. - On Windows you can find the user base binary directory by running
py-msite--user-site
and replacingsite-packages
withScripts
. Forexample, this could returnC:UsersUsernameAppDataRoamingPython36site-packages
so you wouldneed to set yourPATH
to includeC:UsersUsernameAppDataRoamingPython36Scripts
. You can set your userPATH
permanently in the Control Panel. You may need to log out for thePATH
changes to take effect.
Install a list of requirements specified in a Requirements File.
Install a project from VCS in “editable” mode. For a full breakdown of thesyntax, see pip’s section on VCS Support.
Install from an alternate index
Search an additional index during install, in addition to PyPI
Installing from local src in Development Mode,i.e. in such a way that the project appears to be installed, but yet isstill editable from the src tree.
You can also install normally from src
Install a particular source archive file.
Install from a local directory containing archives (and don’t check PyPI)
To install from other data sources (for example Amazon S3 storage) you cancreate a helper application that presents the data in a PEP 503 compliantindex format, and use the --extra-index-url
flag to direct pip to usethat index.
Python 3 On Mac
Find pre-release and development versions, in addition to stable versions. Bydefault, pip only finds stable versions.
Install setuptools extras.
[1] | “Secure” in this context means using a modern browser or atool like curl that verifies SSL certificates when downloading fromhttps URLs. |
[2] | Depending on your platform, this may require root or Administratoraccess. pip is currently considering changing this by making userinstalls the default behavior. |
Manual Install Python On Mac Pro
[3] | Beginning with Python 3.4, venv (a stdlib alternative tovirtualenv) will create virtualenv environments with pip pre-installed, thereby making it an equal alternative tovirtualenv. |
Manual Install Python On Mac Download
[4] | The compatible release specifier was accepted in PEP 440and support was released in setuptools v8.0 andpip v6.0 |