Install and Setup for Raspberry Pi
Python is pre-installed in Raspian. Version 2.7 and 3.6 are the default installations. Python versions can be uninstalled or installed by running the commands:
sudo apt-get uninstall python2.7 sudo apt-get install python3.3
If multiple versions are installed the default version can be setup to run at the command line or inside each virtual environment. To change the version to run use the command
sudo Python -version: "3.3"