centos7 安装python3

    yum install openssl-devel bzip2-devel expat-devel gdbm-devel readline-devel sqlite-devel  mysql-devel gcc gcc-devel python-devel  // 安装相关依赖库

     wget "https://www.python.org/ftp/python/3.5.0/Python-3.5.0.tgz"


     tar -zxvf Python-3.5.0.tgz

     mkdir /usr/local/python3

     yum install gcc(有时候需要)

     Python-3.5.0/configure --prefix=/usr/local/python3

     //cd Python-3.5.0

     make && make install

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

安装pip3 和 virtualenv

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

　　pip install virtualenv

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

　virutalenv -p /usr/bin/python3  虚拟环境目录

 cd 虚拟环境目录

source  ./bin/activate

pip3 使用豆瓣源

或者直接使用   pip3 install -i https://pypi.tuna.tsinghua.edu.cn/simple decouple  xxx(模块名称)