Python两个版本同时使用

Python3.6
计算机->系统属性->高级系统设置->环境变量->
C:\Program Files\Git\cmd;C:\Users\Administrator\AppData\Local\Programs\Python\Python36\python.exe  
#用分号隔开
找到Python.exe改成Python3.exe
Python2.7
C:\Program Files\Git\cmd;C:\Users\Administrator\AppData\Local\Programs\Python\Python36\python.exe；E:\python
找到Python.exe改成Python2.exe
#查看
C:\Users\Administrator>python3
Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 18:41:36) [MSC v.1900 64 bit (AMD64)]
 on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

C:\Users\Administrator>python2
Python 2.7.13 (v2.7.13:a06454b1afa1, Dec 17 2016, 20:42:59) [MSC v.1500 32 bit (
Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>