We highly recommend pyenv to install multiple Python versions side-by-side, which does not interfere with system-default Pythons.

Install dependencies for building Python

Ubuntu

$ sudo apt-get update -y
$ sudo apt-get dist-upgrade -y
$ sudo apt-get install -y \
> build-essential git-core                                     # for generic C/C++ builds
> libreadline-dev libsqlite3-dev libssl-dev libbz2-dev tk-dev  # for Python builds
> libzmq3-dev libsnappy-dev                                      # for Backend.AI dependency builds

CentOS / RHEL

(TODO)

Install pyenv

NOTE: Change ~/.profile accroding to your shell/system (e.g., ~/.bashrc, ~/.bash_profile, ~/.zshrc, …) – whichever loaded at startup of your shell!

$ git clone https://github.com/pyenv/pyenv.git ~/.pyenv
...
$ echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.profile
$ echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.profile
$ echo 'eval "$(pyenv init -)"' >> ~/.profile
$ exec $SHELL -l
$ pyenv  # check installation
pyenv 1.2.0-6-g9619e6b
Usage: pyenv <command> [<args>]

Some useful pyenv commands are:
   ...

Install pyenv’s virtualenv plugin

$ git clone https://github.com/pyenv/pyenv-virtualenv.git ~/.pyenv/plugins/pyenv-virtualenv
...
$ echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.profile
$ exec $SHELL -l
$ pyenv virtualenv  # check installation
pyenv-virtualenv: no virtualenv name given.

Install Python via pyenv

Install Python 3.6 latest version.

Warning

Currently Python 3.7 is not supported yet.

$ pyenv install 3.6.6

Create a virtualenv using a specific Python version

Change myvenv to specific names required in other guide pages.

$ pyenv virtualenv 3.6.6 myvenv

Activate the virtualenv for the current shell

$ pyenv shell myvenv

Activate the virtualenv when your shell goes into a directory

$ cd some-directory
$ pyenv local myvenv

Note

pyenv local creates a hidden .python-version file at each directory specifying the Python version/virtualenv recongnized by pyenv. Any pyenv-enabled shells will automagically activate/deactivate this version/virtualenv when going in/out such directories.