Python - Python2与Python3合理共存Windows平台

╰+哭是因爲堅強的太久メ 2022-05-12 06:33 198阅读 0赞

## Install Python2 and Python3 ##

[Python 2.7.13 - Windows x86-64 MSI installer][]  
[Python 3.6.0 - Windows x86-64 executable installer][]  
Note: For Python 3.3 and later, select the option "Install launcher for all users(recommended)".

**Set Environment Variables**  
Sample:  
`C:\Python27;C:\Python27\Scripts;C:\Python27\Lib\site-packages;`  
`C:\Python36;C:\Python36\Scripts;C:\Python36\Lib\site-packages;`

Check system variables - path : Run the commond `>set path` and check the output.

## Python Launcher for Windows Version ##

[Python Launcher for Windows Version][]

>py -2
    
    Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:24:40) [MSC v.1500 64 bit (AMD64)] on win32
    
    Type "help", "copyright", "credits" or "license" for more information.
    
    >>>
    
    
    >py -3
    
    Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
    
    Type "help", "copyright", "credits" or "license" for more information.
    
    >>>

## Run an sample ##

### Method 1 : python or py ###

>python --version
    
    Python 2.7.13
    
    
    >py --version
    
    Python 3.6.0

### Method 2 : `py -2` or `py -3` ###

>type HelloWorld-py2.py
    
    print 'Hello World! Hello Python!'
    
    >
    
    >py -2 HelloWorld-py2.py
    
    Hello World! Hello Python!
    
    
    
    >type HelloWorld-py3.py
    
    print ('Hello World! Hello Python!')
    
    >
    
    >py -3 HelloWorld-py3.py
    
    Hello World! Hello Python!
    
    >

Note:`py -2.7 HelloWorld-py2.py` and `py -3.6 HelloWorld-py3.py` are recommended.

### Method 3 : Specify the Python version in a script ###

>type HelloWorld-py2.py
    
    #! python2.7
    
    print 'Hello World! Hello Python!'
    
    >
    
    >py HelloWorld-py2.py
    
    Hello World! Hello Python!
    
    
    
    >type HelloWorld-py3.py
    
    #! python3.6
    
    print ('Hello World! Hello Python!')
    
    >
    
    >py HelloWorld-py3.py
    
    Hello World! Hello Python!
    
    >

## pip2 and pip3 ##

Install Python2 Package: `pip2 install <Package_name>` or `py -2 -m pip install <Package_name>`  
Install Python3 Package: `pip3 install <Package_name>` or `py -3 -m pip install <Package_name>`

>pip2 --version
    
    pip 9.0.1 from c:\python27\lib\site-packages (python 2.7)
    
    
    >pip3 --version
    
    pip 9.0.1 from c:\python36\lib\site-packages (python 3.6)

**Run an sample**

>pip3 list --format=legacy
    
    pip (9.0.1)
    
    setuptools (28.8.0)
    
    
    >pip3 install requests --proxy=10.144.1.10:8080
    
    Collecting requests
    
    Downloading requests-2.13.0-py2.py3-none-any.whl (584kB)
    
    100% |████████████████████████████████| 593kB 137kB/s
    
    Installing collected packages: requests
    
    Successfully installed requests-2.13.0
    
    
    >pip3 list --format=legacy
    
    pip (9.0.1)
    
    requests (2.13.0)
    
    setuptools (28.8.0)

## py help ##

$ py -h
    
    Python Launcher for Windows Version 3.6.150.1013
    
    
    usage: py [ launcher-arguments ] [ python-arguments ] script [ script-arguments ]
    
    
    Launcher arguments:
    
    
    -2 : Launch the latest Python 2.x version
    
    -3 : Launch the latest Python 3.x version
    
    -X.Y : Launch the specified Python version
    
    -X.Y-32: Launch the specified 32bit Python version

[Python 2.7.13 - Windows x86-64 MSI installer]: https://www.python.org/ftp/python/2.7.13/python-2.7.13.amd64.msi
[Python 3.6.0 - Windows x86-64 executable installer]: https://www.python.org/ftp/python/3.6.0/python-3.6.0-amd64.exe
[Python Launcher for Windows Version]: https://docs.python.org/3/using/windows.html#python-launcher-for-windows