python packages sites
/usr/lib/python3/dist-packages/
pip installation site
/usr/local/lib/python3.6/dist-packages
pip3 安装包后import 包却找不到,加入放包位置的环境变量
export PYTHONPATH=/usr/local/lib/python3.6/dist-packages:$PYTHONPATH
/usr/lib/python3/dist-packages/
/usr/local/lib/python3.6/dist-packages
export PYTHONPATH=/usr/local/lib/python3.6/dist-packages:$PYTHONPATH