【Python安装配置】Python2和Python3如何共存并使用Pip

1、按照最新版本2.7.13和3.6 默认安装并将安装目录添加到path变量中

2、将python3安装目录下的python.exe 改名为python3.exe（或者直接copy python.exe并重命名为python3.exe，保留原python.exe则不会出现下面pip3 -V 报错的问题）

3、删除 Python3\Scripts下的pip.exe

上述操作完成后，直接在命令行调用python、python3、pip -V、pip3 -V 验证结果：

D:\Users\administrator>python

Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (Intel)] on win32

Type "help", "copyright", "credits" or "license" for more information.

>>> exit()

D:\Users\administrator>python3

Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 07:18:10) [MSC v.1900 32 bit (Intel)] on win32

Type "help", "copyright", "credits" or "license" for more information.

>>> exit()

D:\Users\administrator>pip -V

pip 9.0.1 from d:\python27\lib\site-packages (python 2.7)

D:\Users\administrator>pip3 -V

Fatal error in launcher: Unable to create process using '"'

最后一个报错，经验证是pip3 依赖安装目录下的python.exe，上面改为python3.exe后无法找到依赖关系，没关系，再copy 并重命名一个python.exe，即在Python3目录下有两个.exe文件，再重复上述验证即可。

D:\Users\administrator>pip3 -V

Fatal error in launcher: Unable to create process using '"'

D:\Users\administrator>pip3 -V

pip 9.0.1 from d:\python3\lib\site-packages (python 3.6)

D:\Users\administrator>pip -V

pip 9.0.1 from d:\python27\lib\site-packages (python 2.7)

D:\Users\administrator>python3

Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 07:18:10) [MSC v.1900 32 bit (Intel)] on win32

Type "help", "copyright", "credits" or "license" for more information.

>>> exit()

D:\Users\administrator>python

Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (Intel)] on win32

Type "help", "copyright", "credits" or "license" for more information.

>>> exit()

D:\Users\administrator>

就是这么简单