pig install报错：Could not find a version that satisfies the requirement pandas (from versions: none)

问题描述：

pip install pandas  失败，报错如下：

ERROR: Could not find a version that satisfies the requirement pandas (from versions: none)
ERROR: No matching distribution found for pandas

解决方法：

pip install pandas -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com

原因说明：

网络差。