如果本机安装了python2，尽量不要管他，使用python3运行python脚本就好，因为可能有程序依赖目前的python2环境

安装python3

1. 安装依赖环境

# yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

2.下载Python3

# wget https://www.python.org/ftp/python/3.6.1/Python-3.6.1.tgz

3.安装python3

我个人习惯安装在/usr/local/python3（具体安装位置看个人喜好）
　　创建目录：

# mkdir -p /usr/local/python3

解压安装包

# tar -zxvf Python-3.6.1.tgz

4.进入解压后的目录，编译安装。

# cd Python-3.6.1
# ./configure --prefix=/usr/local/python3

make

# make

make install

make install    或者 make && make install

5.建立python3的软链

# ln -s /usr/local/python3/bin/python3 /usr/bin/python3

6.并将/usr/local/python3/bin加入PATH

编辑.bash_profile文件

# vim ~/.bash_profile

加入PATH

# vim ~/.bash_profile
# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
# User specific environment and startup programs
PATH=$PATH:$HOME/bin:/usr/local/python3/bin
export PATH

修改完记得执行行下面的命令，让上一步的修改生效：

# source ~/.bash_profile

检查Python3及pip3是否正常可用：

# python3 -V
Python 3.6.1
# pip3 -V
pip 9.0.1 from /usr/local/python3/lib/python3.6/site-packages (python 3.6)