树莓派4B换源

　　更换debian源

sudo vi /etc/apt/sources.list

:%s#deb.debian.org#mirrors.tuna.tsinghua.edu.cn#

:%s#security.debian.org#mirrors.tuna.tsinghua.edu.cn#

　　更换树莓派官方软件源

sudo vi /etc/apt/sources.list.d/raspi.list

:%s#archive.raspberrypi.org/debian/#mirrors.tuna.tsinghua.edu.cn/raspberrypi/#

　　更换pip源

sudo vi /etc/pip.conf

　　注释extra-index-url，添加index-url

[global]
#extra-index-url=https://www.piwheels.org/simple
index-url = https://pypi.tuna.tsinghua.edu.cn/simple

 　　更新pip

sudo pip install pip -U