我个人会在PowerShell中完成这一切。
我很想把它写进一个脚本里，就像这样：

[CmdletBinding()] Param(
    $pythonVersion = "3.6.2"
    $pythonUrl = "https://www.python.org/ftp/python/$pythonVersion/python-$pythonVersion.exe"
    $pythonDownloadPath = 'C:\Tools\python-$pythonVersion.exe'
    $pythonInstallDir = "C:\Tools\Python$pythonVersion"
)

(New-Object Net.WebClient).DownloadFile($pythonUrl, $pythonDownloadPath)
& $pythonDownloadPath /quiet InstallAllUsers=1 PrependPath=1 Include_test=0 TargetDir=$pythonInstallDir
if ($LASTEXITCODE -ne 0) {
    throw "The python installer at '$pythonDownloadPath' exited with error code '$LASTEXITCODE'"
}
# Set the PATH environment variable for the entire machine (that is, for all users) to include the Python install dir
[Environment]::SetEnvironmentVariable("PATH", "${env:path};${pythonInstallDir}", "Machine")

然后你可以从cmd调用脚本。exe像这样：

Powershell.exe -File X:\Path\to\Install-Python.ps1

Param()块定义了Python版本的默认值、下载它的URL、保存它的位置和安装它的位置，但是如果有用的话，可以覆盖这些选项。你可以像这样传递这些参数：

Powershell.exe -File X:\Path\to\Install-Python.ps1 -version 3.4.0 -pythonInstallDir X:\Somewhere\Else\Python3.4.0

也就是说，你完全可以在纯Powershell中做一个单行程序。从你的描述中，我认为你不应该需要做start cmd /k前缀-你应该能够只调用PowerShell。直接执行，像这样：

powershell -command "(New-Object Net.WebClient).DownloadFile('https://www.python.org/ftp/python/3.6.2/python-3.6.2.exe', 'C:/Tools/python-3.6.2.exe'); & c:\Tools\python-3.6.2.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0 TargetDir=c:\Tools\Python362; [Environment]::SetEnvironmentVariable('PATH', ${env:path} + ';C:\Tools\Python362', 'Machine')"

在PowerShell中完成这一切，包括安装库。

# This is the link to download Python 3.6.7 from Python.org
# See https://www.python.org/downloads/
$pythonUrl = "https://www.python.org/ftp/python/3.6.7/python-3.6.7-amd64.exe"

# This is the directory that the exe is downloaded to
$tempDirectory = "C:\temp_provision\"

# Installation Directory
# Some packages look for Python here
$targetDir = "C:\Python36"

# create the download directory and get the exe file
$pythonNameLoc = $tempDirectory + "python367.exe"
New-Item -ItemType directory -Path $tempDirectory -Force | Out-Null
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
(New-Object System.Net.WebClient).DownloadFile($pythonUrl, $pythonNameLoc)

# These are the silent arguments for the install of python
# See https://docs.python.org/3/using/windows.html
$Arguments = @()
$Arguments += "/i"
$Arguments += 'InstallAllUsers="1"'
$Arguments += 'TargetDir="' + $targetDir + '"'
$Arguments += 'DefaultAllUsersTargetDir="' + $targetDir + '"'
$Arguments += 'AssociateFiles="1"'
$Arguments += 'PrependPath="1"'
$Arguments += 'Include_doc="1"'
$Arguments += 'Include_debug="1"'
$Arguments += 'Include_dev="1"'
$Arguments += 'Include_exe="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += 'InstallLauncherAllUsers="1"'
$Arguments += 'Include_lib="1"'
$Arguments += 'Include_pip="1"'
$Arguments += 'Include_symbols="1"'
$Arguments += 'Include_tcltk="1"'
$Arguments += 'Include_test="1"'
$Arguments += 'Include_tools="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += 'Include_launcher="1"'
$Arguments += "/passive"

#Install Python
Start-Process $pythonNameLoc -ArgumentList $Arguments -Wait

Function Get-EnvVariableNameList {
    [cmdletbinding()]
    $allEnvVars = Get-ChildItem Env:
    $allEnvNamesArray = $allEnvVars.Name
    $pathEnvNamesList = New-Object System.Collections.ArrayList
    $pathEnvNamesList.AddRange($allEnvNamesArray)
    return ,$pathEnvNamesList
}

Function Add-EnvVarIfNotPresent {
Param (
[string]$variableNameToAdd,
[string]$variableValueToAdd
   ) 
    $nameList = Get-EnvVariableNameList
    $alreadyPresentCount = ($nameList | Where{$_ -like $variableNameToAdd}).Count
    if ($alreadyPresentCount -eq 0)
    {
    [System.Environment]::SetEnvironmentVariable($variableNameToAdd, $variableValueToAdd, [System.EnvironmentVariableTarget]::Machine)
    [System.Environment]::SetEnvironmentVariable($variableNameToAdd, $variableValueToAdd, [System.EnvironmentVariableTarget]::Process)
    [System.Environment]::SetEnvironmentVariable($variableNameToAdd, $variableValueToAdd, [System.EnvironmentVariableTarget]::User)
        $message = "Enviromental variable added to machine, process and user to include $variableNameToAdd"
    }
    else
    {
        $message = 'Environmental variable already exists. Consider using a different function to modify it'
    }
    Write-Information $message
}

Function Get-EnvExtensionList {
    [cmdletbinding()]
    $pathExtArray =  ($env:PATHEXT).Split("{;}")
    $pathExtList = New-Object System.Collections.ArrayList
    $pathExtList.AddRange($pathExtArray)
    return ,$pathExtList
}

Function Add-EnvExtension {
Param (
[string]$pathExtToAdd
   ) 
    $pathList = Get-EnvExtensionList
    $alreadyPresentCount = ($pathList | Where{$_ -like $pathToAdd}).Count
    if ($alreadyPresentCount -eq 0)
    {
        $pathList.Add($pathExtToAdd)
        $returnPath = $pathList -join ";"
        [System.Environment]::SetEnvironmentVariable('pathext', $returnPath, [System.EnvironmentVariableTarget]::Machine)
        [System.Environment]::SetEnvironmentVariable('pathext', $returnPath, [System.EnvironmentVariableTarget]::Process)
        [System.Environment]::SetEnvironmentVariable('pathext', $returnPath, [System.EnvironmentVariableTarget]::User)
        $message = "Path extension added to machine, process and user paths to include $pathExtToAdd"
    }
    else
    {
        $message = 'Path extension already exists'
    }
    Write-Information $message
}

Function Get-EnvPathList {
    [cmdletbinding()]
    $pathArray =  ($env:PATH).Split("{;}")
    $pathList = New-Object System.Collections.ArrayList
    $pathList.AddRange($pathArray)
    return ,$pathList
}

Function Add-EnvPath {
Param (
[string]$pathToAdd
   ) 
    $pathList = Get-EnvPathList
    $alreadyPresentCount = ($pathList | Where{$_ -like $pathToAdd}).Count
    if ($alreadyPresentCount -eq 0)
    {
        $pathList.Add($pathToAdd)
        $returnPath = $pathList -join ";"
        [System.Environment]::SetEnvironmentVariable('path', $returnPath, [System.EnvironmentVariableTarget]::Machine)
        [System.Environment]::SetEnvironmentVariable('path', $returnPath, [System.EnvironmentVariableTarget]::Process)
        [System.Environment]::SetEnvironmentVariable('path', $returnPath, [System.EnvironmentVariableTarget]::User)
        $message = "Path added to machine, process and user paths to include $pathToAdd"
    }
    else
    {
        $message = 'Path already exists'
    }
    Write-Information $message
}

Add-EnvExtension '.PY'
Add-EnvExtension '.PYW'
Add-EnvPath 'C:\Python36\'

# Install a library using Pip
python -m pip install numpy

下面是我为windows准备的一些东西，用于检查endoflife.date/api的最新python版本，在C上下载它：驱动并包含Python到用户的路径：

@echo off
setlocal EnableDelayedExpansion

set url=https://endoflife.date/api/python.json

set "response="
for /f "usebackq delims=" %%i in (`powershell -command "& {(Invoke-WebRequest -Uri '%url%').Content}"`) do set "response=!response!%%i"

set "latest_py_version="
for /f "tokens=1,2 delims=}" %%a in ("%response%") do (
    set "object=%%a}"
    for %%x in (!object!) do (
        for /f "tokens=1,* delims=:" %%y in ("%%x") do (
            if "%%~y" == "latest" (
                set "latest_py_version=%%~z"
            )
        )
    )
)

echo %latest_py_version%

REM Set the minimum required Python version
set python_version=%latest_py_version%

REM Check if Python is already installed and if the version is less than python_version
echo Checking if Python %python_version% or greater is already installed...
set "current_version="
where python >nul 2>nul && (
    for /f "tokens=2" %%v in ('python --version 2^>^&1') do set "current_version=%%v"
)
if "%current_version%"=="" (
    echo Python is not installed. Proceeding with installation.
) else (
    if "%current_version%" geq "%python_version%" (
        echo Python %python_version% or greater is already installed. Exiting.
        pause
        exit
    )
)

REM Define the URL and file name of the Python installer
set "url=https://www.python.org/ftp/python/%python_version%/python-%python_version%-amd64.exe"
set "installer=python-%python_version%-amd64.exe"

REM Define the installation directory
set "targetdir=C:\Python%python_version%"

REM Download the Python installer
echo Downloading Python installer...
powershell -Command "(New-Object Net.WebClient).DownloadFile('%url%', '%installer%')"

REM Install Python with a spinner animation
echo Installing Python...
start /wait %installer% /quiet /passive TargetDir=%targetdir% Include_test=0 ^
&& (echo Done.) || (echo Failed!)
echo.

REM Add Python to the system PATH
echo Adding Python to the system PATH...
setx PATH "%targetdir%;%PATH%"
if %errorlevel% EQU 1 (
  echo Python has been successfully installed to your system BUT failed to set system PATH. Try running the script as administrator.
  pause
  exit
)
echo Python %python_version% has been successfully installed and added to the system PATH.

REM Cleanup
echo Cleaning up...
del %installer%

echo Done!
pause