Enable-Python script allows to switch between differen versions of Python installed on Windows machine

Enable-Python.ps1

# copy the code to $PROFILE.CurrentUserAllHosts
# and restard PowerShell.
# Now you can switch between different versions of Python using EnablePython <Version>
# or short aliases: py36, py37, py38

Function Get-OriginalPath {
    if (-not $env:ORIGINAL_PATH) {
        $env:ORIGINAL_PATH = $env:PATH
    }
    return $env:ORIGINAL_PATH
}

Function Get-PythonBasePath {
    $env:LOCALAPPDATA + '\Programs\Python'
}

Function Get-AvailablePythons {
    Get-PythonBasePath | Get-ChildItem | Foreach-Object {
        $_.Name.ToString()
    }
}

Function Enable-Python ([string] $Version) {
    $AvailableVersions = Get-AvailablePythons

    if ($Version -in $AvailableVersions) {
        $originalPath = Get-OriginalPath
        $basePythonPath = Get-PythonBasePath
        $pythonPath = $basePythonPath + "\" + $Version
        $pythonScriptsPath = $pythonPath + "\Scripts"
        $env:Path = $pythonPath + ";" + $pythonScriptsPath + ";" + $originalPath
    } else {
        Write-Output "$Version is not available. Please select one of $AvailableVersions"
    }
}

Function py36 {
    Enable-Python Python36
}

Function py37 {
    Enable-Python Python37
}

Function py38 {
    Enable-Python Python38
}