更改命令提示符的默认 python 版本

Question

On my machine I have python3.4 and a recently downloaded python3.6 installed, I would like to set python3.6 as my default python used in command prompt.

I have removed the python34 path variable but my when I access python through the command prompt it still defaults to opening python3.4. I saw this question about access the non default python but that was for specific files.

Since posting the question:

I have also removed python34 from the system path variables.

Typing where python in command prompt returns this:

C:\>where python
C:\Python34\python.exe
C:\Python36\python.exe

Typing echo %PATH% returns

C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\iCLS\;C:\Program Files\Intel\Intel(R) Management Engine Components\iCLS\;C:\ProgramData\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Microsoft SQL Server\Client SDK\ODBC\130\Tools\Binn\;C:\Program Files (x86)\Microsoft SQL Server\140\Tools\Binn\;C:\Program Files (x86)\Microsoft SQL Server\140\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL Server\140\Tools\Binn\ManagementStudio\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\Python34;;C:\WINDOWS\System32\OpenSSH\;C:\Python36\Scripts\;C:\Python36\;C:\Users\ME\AppData\Local\Microsoft\WindowsApps;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;

The accepted answer on the proposed duplicate states it is possible but you shouldn't do it, and doesn't give details on how to do it.

Answer 1

You can run multiple python versions on your machine.

To make Python 3.6 default, just put path of Python 3.6 before path of Python 3.4 in system variables.

OR

In python34 directory on C drive rename python.exe to python3.4.exe. After doing this if you run command python in command prompt it will open python 3.6. And to run python 3.4 you need to run command python3.4 as we have renamed it to python3.4.exe in python34 directory .

After making changes in system variables in environment variables you just need to restart your command prompt. No need to restart machine.

Answer 2

After some communication I guess I know what is the problem. Have you checked your system wide environment variables? Here is a link about how to:

1. In Search, search for and then select: System (Control Panel)
2. Click the Advanced system settings link.
3. Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
4. In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.

Further, your application(your command prompt) wide environment variables are appended after system wide ones.

Answer 3

After doing a restart of my machine after deleting python34 from my system path variables as @Talha Junaid mentioned in the comments, my python now defaults to python3.6 when accessed through command prompt, windows must load all the path variables on startup and hold them in memory until a restart occurs.

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Steps for anyone else starting the process.

Windows 10

1. Type "System" into the search bar to go to system settings in the control panel (Control Panel\\All Control Panel Items\\System)

2. Click "Advanced System Settings" -> 2Environment Variables2

For User Variables:

3. Highlight the row for "Path" by clicking on it and then click the "Edit" button
4. Highlight by clicking the version of python you want to remove from your environment variables and then click the "Delete" button.

Repeat steps 3 and 4 for System Environment Variables.

5. Close all the windows by clicking the "Ok" buttons

6. Restart your machine

Answer 4

我遇到了同样的问题，在将 python.exe 更改为 python3.6.exe 后，我从 Windows 商店下载了版本 8，并且安装和替换自动完成，并且默认版本也更新了。