In PowerShell, Get-Command python | fl * will tell you which Python executable it's finding and show you details about where it is.
- You can check Settings -> Apps and Features, or Control Panel -> Programs and Features. They will show you distinct versions of Python you installed, but that might not be enough if Python is installed as part of some other toolkit or program.
- If Python 2.7.11 is there, select it and click uninstall. If it's not there, see if you can tell what it's installed with, from the output of
Get-Commandearlier, and decide if you want to remove that. - How PowerShell chooses what to run when you type a command is explained in help about_Command_Precedence, and is:
- Alias
- Function
- Cmdlet
- Native Windows commands
At the point of "Native Windows commands", it goes to the PATH environment variable, a semi-colon separated list of path names, which get searched in order, looking for a matching executable file.
You can see the folders with:
$Env:PATH -split ';'
And you can watch PowerShell identify what to run for 'python' with the command
Trace-Command –Name CommandDiscovery –Expression {get-command python} -PSHost
So, to make Python 2.7.13 the one to launch, you could:
- make it the only Python version available.
- move its folder to the front of the PATH list, ahead of any other version. See: What are path and other environment variables, and how can I set or use them - question on SuperUser.com
- make a batch file to launch it called python.bat in a folder in the PATH ahead of other versions.
- make an alias (in your PS Profile) named python to launch the one you want (
New-Alias -name python -Value C:\Python27\python.exe, etc).
In PowerShell, Get-Command python | fl * will tell you which Python executable it's finding and show you details about where it is.
- You can check Settings -> Apps and Features, or Control Panel -> Programs and Features. They will show you distinct versions of Python you installed, but that might not be enough if Python is installed as part of some other toolkit or program.
- If Python 2.7.11 is there, select it and click uninstall. If it's not there, see if you can tell what it's installed with, from the output of
Get-Commandearlier, and decide if you want to remove that. - How PowerShell chooses what to run when you type a command is explained in help about_Command_Precedence, and is:
- Alias
- Function
- Cmdlet
- Native Windows commands
At the point of "Native Windows commands", it goes to the PATH environment variable, a semi-colon separated list of path names, which get searched in order, looking for a matching executable file.
You can see the folders with:
$Env:PATH -split ';'
And you can watch PowerShell identify what to run for 'python' with the command
Trace-Command –Name CommandDiscovery –Expression {get-command python} -PSHost
So, to make Python 2.7.13 the one to launch, you could:
- make it the only Python version available.
- move its folder to the front of the PATH list, ahead of any other version. See: What are path and other environment variables, and how can I set or use them - question on SuperUser.com
- make a batch file to launch it called python.bat in a folder in the PATH ahead of other versions.
- make an alias (in your PS Profile) named python to launch the one you want (
New-Alias -name python -Value C:\Python27\python.exe, etc).
This was a question about python 2.7, but probably it will be useful to give an answer for the versions above 3.3 too:
Previously, multiple versions (also environments, also they are specific folders) of python on the same system was rare, and placing the only available python.exe directly in PATH was acceptable. Currently, multiple installed python versions will conflict and override each other if simply placed that way.
After 3.3 a python launcher was introduced which detects and activates one of the installed versions automatically. It is supposed to be placed in PATH instead of any python executable.
So in this modern situation, Get-Command python | fl * may give you nothing or nothing helpful.
And to run scripts or to get available versions, use launcher:
- ensure you have it:
tryGet-Command pycommand from the PowerShell. If launcher is missing, it can be installed with the official installer. There is a separate checkbox for the launcher which is enabled by default. - if install is correct, command
py --list-pathswill give a summary on the installed versions, and supposed way to run scripts is not previouspython main.py, but commands likepy main.pyorpy -3.5 main.py. Runpy --helpfor more info.
Additional confirmation that intended way changed.
Just to give an idea, launcher is not the only way to activate, this also can be done by a simple command.
For example, there is a version under D:\python_install\python.exe. But it's not in the PATH and python command correctly ends with not found error or opens Windows Store. An additional command in cmd or bat SET PATH=D:\python_install\;%PATH% or PowerShell $env:Path = "D:\python_install\;" + $env:Path temporarily activates that specific version, and python will work as previously during that specific run.
Possibly because after python 3.3 intended command is not python, but simply py
Detailed explanation here
And short answer to your question:
check if powershell command py -0p --list-paths finds any versions.
I am using Windows 11, Python3.10 and Laptop, and Windows Powershell cannot show Python version (command: python --version).
Solution: type Python inside Windows Powershell, it will prompt out Microsoft Store, just click "get", wait to finish the process, then go to Windows Powershell, type "python --version", it can show the Python version.
Windows powershell starts old python
Why doesn't python 3.10.0 show up on PowerShell?
Powershell script to check if Python is installed - Stack Overflow
Installing python 3.8 but getting 2.7 in CMD/Powershell?
How to check the Python version on CMD?
What is a Python version file?
How do I change the Python version?
Videos
It seems that python -V outputs the version string to stderr and not stdout.
You can use a stream redirector to redirect the error into the standard output:
# redirect stderr into stdout
$p = &{python -V} 2>&1
# check if an ErrorRecord was returned
$version = if($p -is [System.Management.Automation.ErrorRecord])
{
# grab the version string from the error message
$p.Exception.Message
}
else
{
# otherwise return as is
$p
}
If you are certain that all the versions of python you have on your systems will behave this way, you can cut it down to:
$version = (&{python -V}).Exception.Message
For python above 3.3, a launcher was introduced which may be installed automatically or manually as part of official installer.
In modern situation, command python -V may give you error or nothing helpful (python may not even be presented in PATH by default), but launcher is supposed to be used both for checking installed python versions:
py -0p --list-paths
and to run scripts: py -3.11 main.py or simply py main.py
Discussion which confirms.