参考:
安装anaconda2+tensorflow: https://blog.youkuaiyun.com/wyz6666/article/details/78440272
在安装anaconda2之后安装anaconda3: https://blog.youkuaiyun.com/u014044032/article/details/82223932
我先装的anaconda3-->再安装的anaconda2
这样默认的python环境是3.6
切换到python2.7,需要激活python2.7所在的环境
source activate py2 (py2 是安装anaconda2所创建的环境)
推出python2.7
source deactivate py2