centos中 系统自带python2 无法使用pip命令:
yum -y install epel-release
yum install python-pip
升级pip:(可选)
pip install --upgrade pip
-----------------------
pip无法安装或者安装速度慢:
vim ~/.pip/pip.cnf
[global]
index-url = http://mirrors.aliyun.com/pypi/simple/
[install]
trusted-host = mirrors.aliyun.com
如果速度还慢,重启尝试