Installing a separate copy of Python is a popular option, even though Python already comes with macOS. You take on the responsibility to make sure you're using the copy of Python you intend. But, the benefits are having the latest Python release and some protection from hosing your system if things go badly wrong.
To install Python using HomeBrew:
brew update
brew install python # or brew install python3
Now confirm that we're working with our newly installed Python:
ls -lh `which python`
...should show a symbolic link to a path with "Cellar" in it like:
lrwxr-xr-x 1 chris admin 35B Dec 2 13:40 /usr/local/bin/python -> ../Cellar/python/2.7.8_2/bin/python
Pip should be installed along with Python. You might want to upgrade it by typing:
pip install --upgrade pip
Now you're ready to install any of the 50,000+ packages on PyPI.
Other Notes
Formerly, I've used get-pip.py to install pip. But, the docs warn that get-pip.py does not coordinate with package managers and may leave your system in an inconsistent state. Anyway, there's no need, given that pip is now included with Python as of 2.7.9.
Note that pip isn't the only package manager for Python. There's also easy_install. It's no good to mix the two, so don't do it.
Finally, if you have both Python 2 and 3 installed, pip will point to whichever Python you installed last. Get in the habit of explicitly using either pip2 or pip3, so you're sure which Python is getting the new library.
Happy hacking!
Mac OS X comes with Python 2.7 out of the box.
You do not need to install or configure anything else to use Python. Having said that, I would strongly recommend that you install the tools and libraries described in the next section before you start building Python applications for real-world use. In particular, you should always install Setuptools, as it makes it much easier for you to install and manage other third-party Python libraries.
The version of Python that ships with OS X is great for learning, but it’s not good for development. The version shipped with OS X may be out of date from the official current Python release, which is considered the stable production version.
Doing it Right¶
Let’s install a real version of Python.
Before installing Python, you’ll need to install a C compiler. The fastest way is to install the Xcode Command
Line Tools by running xcode-select --install. You can also download the full version of Xcode from the Mac App Store, or the minimal but unofficial OSX-GCC-Installer package.
Note
If you already have Xcode installed, do not install OSX-GCC-Installer. In combination, the software can cause issues that are difficult to diagnose.
Note
If you perform a fresh install of Xcode, you will also need to add the commandline tools by running xcode-select --install on the terminal.
While OS X comes with a large number of Unix utilities, those familiar with Linux systems will notice one key component missing: a decent package manager. Homebrew fills this void.
To install Homebrew, open Terminal or your favorite OS X
terminal emulator and run
$ /usr/bin/ruby -e "$[curl -fsSL //raw.githubusercontent.com/Homebrew/install/master/install]"
The script will explain what changes it will make and prompt you before the installation begins. Once you’ve installed Homebrew, insert the Homebrew directory at the top of your PATH environment variable. You can do this by adding the following line at the bottom of your ~/.profile file
export PATH="/usr/local/bin:/usr/local/sbin:$PATH"
Now, we can install Python 2.7:
Because python@2 is a “keg”, we need to update our PATH again, to
point at our new installation:
export PATH="/usr/local/opt/python@2/libexec/bin:$PATH"
Homebrew names the executable python2 so that you can still run the system Python via the executable python.
$ python -V # Homebrew installed Python 3 interpreter [if installed] $ python2 -V # Homebrew installed Python 2 interpreter $ python3 -V # Homebrew installed Python 3 interpreter [if installed]
Virtual Environments¶
A Virtual Environment [commonly referred to as a ‘virtualenv’] is a tool to keep the dependencies required by different projects in separate places, by creating virtual Python environments for them. It solves the “Project X depends on version 1.x but, Project Y needs 4.x” dilemma, and keeps your global site-packages directory clean and manageable.
For example, you can work on a project which requires Django 1.10 while also maintaining a project which requires Django 1.8.
To start using this and see more information: Virtual Environments docs.
This page is a remixed version of another guide, which is available under the same license.