Ubuntu16.04 a perfect switch to the Python version __python

Ubuntu 16.04 itself is a python, and he's a 2-self. X and 3.X, two versions, the default is 2. X. Here's a note of how to switch between versions and how to switch the Python version to 3. The method under X.

1. View the installed Python version of the Ubuntu system and the Python version currently in use

Ls/usr/bin/python*python--version

Or

2. Set update-alternatives switch python version

Show Python instead of version information

Update-alternatives--list python

Show after execution

Update-alternatives:error:no Alternatives for Python indicates that the Python replacement version is not installed

Perform the command installation

Update-alternatives--install/usr/bin/python python/usr/bin/python2.7 1

update-alternatives:using/usr/bin/python2.7 to Provide/usr/bin/python (python) in auto mode

Update-alternatives--install/usr/bin/python python/usr/bin/python3.5 2

update-alternatives:using/usr/bin/python3.5 to Provide/usr/bin/python (python) in auto mode

View the default version

Python--version

In the above command, because we set the priority of/usr/bin/python3.5 setting to 2, update-alternatives commands to set 3.5 as the default

Show Python instead of version information again

Update-alternatives--list python

Toggle version Update-alternatives--config python

Select an ordinal to toggle.