安装requirements总包

pip install -i https://pypi.doubanio.com/simple/ -r requirements.txt

安装单个包

 pip --default-timeout=100 install tensorflow==2.0.0 -i https://pypi.tuna.tsinghua.edu.cn/simple 

pip --default-timeout=100 install tensorflow==2.0.0 -i https://pypi.douban.com/simple

pip install python-snappy报错，需要：

yum install gcc-c++

yum install snappy-devel