You are using pip version 9.0.1, however version 19.0.2 is available. You should consider upgrading

在windows下使用pip安装时出现提示:You are using pip version 9.0.1, however version 19.0.2 is available.
You should consider upgrading via the ‘python -m pip install --upgrade pip’ command.


说明pip版本太低,这时需要使用python -m pip install --upgrade pip命令来更新安装包.
但是在命令执行retry几次之后,又会发现更新失败,具体原因是镜像源的问题,我又重新尝试命令:
将镜像源改为国内的,此处使用豆瓣,问题解决了.
再尝试使用pip安装几个包,还是在命令后加上国内镜像源地址:
OK,perfect!!!