How to configure the default Python version of Ubuntu

ubuntu 16.04本身是自带python的，他本身是自带2.X和3.X,两个版本，默认的是2.X。这里记录一下如果在版本间切换以及如何把python版本切换到3.X下的方法。

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

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

2. Set Update-alternatives to toggle Python version

Show python in place of version information

Update-alternatives--list python

Show after execution

Update-alternatives:error:no alternatives for Python means Python replaces version not yet installed

Perform a 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

Because we set the/usr/bin/python3.5 setting to a priority of 2 in the above command, the update-alternatives command itself sets 3.5 as the default

Show Python instead of version information again

Update-alternatives--list python

Toggle version Update-alternatives--config python sudo update-alternatives --config python 3.python3 version installation pipsudo apt-get install PYTHON3-PIP running pip3-v display version upgrade PIP version PIP3 install--upgrade pip

How to configure the default Python version of Ubuntu