CentOS7 安装python3

由于CentOS7自带的python版本为2.7，所以需要自己安装python3

1、安装依赖包

yum install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gcc make 

2、安装wget

yum install wget

3、使用wget下载python3.7

wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz

4、进入python源码包目录，解压python源码包并手动编译，在执行make && make install时，如果报错

ModuleNotFoundError: No module named '_ctypes'

需要安装libffi-devel，yum install libffi-devel -y 

 #解压
 xz -d Python-3.6.4.tar.xz
 tar -xf Python-3.6.4.tar
 
 #进入解压后的目录，依次执行下面命令进行手动编译
 ./configure prefix=/usr/local/python3
 make && make install

5、添加软链接

ln -s /usr/local/python3/bin/python3 /usr/bin/python
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3