Python 3发布3.5版本，看了PEP新特性，还是非常棒。安装python3.5，并搭建相应的环境。
安装python3.5
官网网站下载python3.5的mac安装文件。安装3的同时，是不会影响2.X的，两个版本可以共存啦。
创建 virtulenv 环境
安装python3.5之后，3.x版本的包响应也在后面加个3，例如 pip和pip3
☁ python3 python
python python3 python3.4m python3.5m-config
python-config python3-32 python3.4m-config pythonw
python2.6 python3-config python3.5 pythonw2.6
python2.6-config python3.4 python3.5-32 pythonw2.7
python2.7 python3.4-32 python3.5-config
python2.7-config python3.4-config python3.5m
☁ python3 which python
/usr/bin/python
☁ python3 which python3
/usr/local/bin/python3
☁ python3 which pip
/usr/local/bin/pip
☁ python3 which pip3
/usr/local/bin/pip3
需要创建一个 虚拟环境，运行：
virtualenv -p python3 venv
该命令使用系统的python3来创建虚拟环境，激活venv环境，查看python版本
☁ python3 source venv/bin/activate
(venv)☁ python3 which python
/Users/ghost/Rsj217/python3/venv/bin/python
(venv)☁ python3 which python3
/Users/ghost/Rsj217/python3/venv/bin/python3
(venv)☁ python3 python
Python 3.5.0 (v3.5.0:374f501f4567, Sep 12 2015, 11:00:19)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>
此时虚拟环境使用的就是python3.5啦
安装ipython适合3.5的版本
激活venv虚拟环境，使用 pip3直接安装 ipython
(venv)☁ python3 pip3 install ipython
...
(venv)☁ python3 which ipython
/Users/ghost/Rsj217/python3/venv/bin/ipython
(venv)☁ python3 ipython
Python 3.5.0 (v3.5.0:374f501f4567, Sep 12 2015, 11:00:19)
Type "copyright", "credits" or "license" for more information.
IPython 4.0.0 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help -> Python's own help system.
object? -> Details about 'object', use 'object??' for extra details.
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That's all， enjoy~
