How to change python default version in ubuntu?

 In ubuntu By default python version was 2.7. We need to use python3 to run the python files with the latest version.

Steps to change the default python version to 3

Check the current version 

#python --version

Python 2.7.17

Execute this command to switch to python 3.6. 

#sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 1

Output:

sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 1

update-alternatives: using /usr/bin/python3 to provide /usr/bin/python (python) in auto mode

Check python version

python --version

Python 3.6.9