I want to use python 3.6 on my Ubuntu 16.04 LTS box; they only have python3.5. It’s pretty simple following these instructions but here’s the details.
Step 1: install python 3.6 from Jonathon Fernyhough’s PPA.
add-apt-repository ppa:jonathonf/python-3.6 apt-get update apt-get install python3.6 python3.6-venv python3.6-dev
Step 2: set up a 3.6 venv
python3.6 -m venv venv source venv/bin/activate pip install -U setuptools pip python -V
Now when you activate venv, you’ll automatically get python 3.6 in that environment.
In addition to the jonathonf PPAs there’s also the deadsnakes PPA which has old versions of Python as well as new ones.