ubuntu16.04下python2、python3环境选择与python升级

参考链接：https://www.jianshu.com/p/63c1f22e1fed

Ubuntu中python版本问题：

• 添加PPA：

sudo add-apt-repository ppa:jonathonf/python-3.6

• 查看更新和安装更新：

sudo apt-get update 
sudo apt-get install python3.6

• 更换命令行中的python默认版本

sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 100
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 150

• 查看python默认版本 

python -V

• 切换版本：

sudo update-alternatives --config python3

Ubuntu中python升级到3.6：

sudo add-apt-repository ppa:jonathonf/python-3.6
sudo apt-get update
sudo apt-get install python3.6

sudo apt install spyder3
sudo rm /usr/bin/python
sudo ln -s /usr/local/bin/python3.6 /usr/bin/python

sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.5 1 
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.6 2 
sudo update-alternatives --config python3
python -V

更新：

2018-05-29 08:58:06

 升级到python3.6 后使用pip install遇到问题：

    import apt
  File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>
    import apt_pkg
ModuleNotFoundError: No module named 'apt_pkg'

Original exception was:
Traceback (most recent call last):
  File "/home/osk/.local/bin/pip3", line 7, in <module>
    from pip._internal import main
ModuleNotFoundError: No module named 'pip._internal'

解决方案：

重新将ubuntu16.04默认的python3.5版本设置为优先级