ubuntu18.04如何安装python3.5及其pip安装

安装python3.5，ubuntu18.04默认python3.6，该版本部分库没有资源无法安装，所以更换为python3.5
参考原文链接：http://blog.itpub.net/69989353/viewspace-2738095/

sudo apt-get update

sudo apt-get install software-properties-common

sudo add-apt-repository ppa:deadsnakes/ppa

sudo apt-get update

sudo apt-get install python3.5-dev

sudo apt-get --reinstall install python3.5-minimal

sudo mv /usr/bin/python3 /usr/bin/python3-old

sudo ln -s /usr/bin/python3.5 /usr/bin/python3

sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.5 300

验证python3.5是否安装成功并且python3已经修改为默认使用3.5：

root@YZ:~/1808-demo/test/rknn# python3 -V
Python 3.5.10

安装新版pip：

wget https://bootstrap.pypa.io/3.5/get-pip.py

sudo python3 get-pip.py

sudo pip3 install setuptools --upgrade

sudo ln -s /usr/local/bin/pip3 /usr/bin/pip3

验证pip安装成功且默认使用python3.5的pip工具：

root@YZ:~/1808-demo/test/rknn# pip -V
pip 20.3.4 from /usr/local/lib/python3.5/dist-packages/pip (python 3.5)