The first thing you should know about pyenv is that it only supports macOS and Linux. The maintainer said that they are not going to spend the time require to support Windows. As an alternative, there is a nacent port of pyenv to windows: pyenv-win. But it specifically states that "Some commands doesn't implemented" and I have not utilized it, so I do not know how well it works.
The second thing you should know about pyenv is that it is hands down the best (and to my mind, only) way to manage multiple versions of Python on macOS and Linux. You can install, uninstall, manually select, and automatically select any supported version of Python.
If you are on macOS, the easiest way to install it is via homebrew:
brew install pyenv
After that you can learn all about what pyenv can do though it's help sub-command:
pyenv help Usage: pyenv <command> [<args>] Some useful pyenv commands are: commands List all available pyenv commands local Set or show the local application-specific Python version global Set or show the global Python version shell Set or show the shell-specific Python version install Install a Python version using python-build uninstall Uninstall a specific Python version rehash Rehash pyenv shims (run this after installing executables) version Show the current Python version and its origin versions List all Python versions available to pyenv which Display the full path to an executable whence List all Python versions that contain the given executable See 'pyenv help <command>' for information on a specific command. For full documentation, see: https://github.com/pyenv/pyenv#readme
To install Python 3.7.0 for example:
pyenv install 3.7.0
This will download, compile, and make available Python version 3.7.0 from your home directory. One of the benefits of this is that all installed site-packages will be stored alongside this install of Python as part of it.
The uiltity provided by pyenv does not stop at downloading and compiling multiple versions of Python. It also facilitates usage of those versions in several user directed ways. The first way is though a .python-version file. When you include this file in a directory, it directs pyenv to switch to providing that version when you change into that directory.
$ python --version Python 2.7.10 $ mkdir demo $ echo "3.7.2" >> demo/.python-version $ cd demo $ python --version Python 3.7.2
The next way to affect the python version that pyenv provides is through the local, global, and shell. They allow for the Python version provided at those scopes to be set.
Finally, if you run into trouble, your first stop in troubleshooting should be the pyenv wiki. I have yet to encounter a problem that did not have an answer somewhere in that wiki.
Good Luck & Happy Hacking,