1.1.2 认识Python

安装Python3.7

// 1.只检查，不更新

sudo apt update

//2. install software-properties-common

sudo apt install software-properties-common

//3.获取最新的个人软件包档案源，将其添加至当前apt库中，并自动导入公钥

sudo add-apt-repository ppa:deadsnakes/ppa

//4.intall python

sudo apt install python3.7

//5.check version of python

python3.7 --version