如何添加和删除系统的环境variables“path”？

 import _winreg as reg import win32gui import win32con # read the value key = reg.OpenKey(reg.HKEY_CURRENT_USER, 'Environment', 0, reg.KEY_ALL_ACCESS) # use this if you need to modify the system variable and if you have admin privileges #key = reg.OpenKey(reg.HKEY_LOCAL_MACHINE, r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment', 0, reg.KEY_ALL_ACCESS) try value, _ = reg.QueryValueEx(key, 'PATH') except WindowsError: # in case the PATH variable is undefined value = '' # modify it value = ';'.join([s for s in value.split(';') if not r'\myprogram' in s]) # write it back reg.SetValueEx(key, 'PATH', 0, reg.REG_EXPAND_SZ, value) reg.CloseKey(key) # notify the system about the changes win32gui.SendMessage(win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 'Environment') 

这是一些你想要的东西，它和jaraco.windows项目中的代码类似。 就像它一样， 只使用内置的Python模块 –不需要先下载和安装pywin32扩展。 另外它的Python 2.6+和3.x兼容，并支持Unicode环境变量和值 （在这种情况下是目录路径）。

请注意，需要Windows管理员权限才能更改永久的系统级环境变量。

 import ctypes from ctypes.wintypes import HWND, UINT, WPARAM, LPARAM, LPVOID LRESULT = LPARAM # synonymous import os import sys try: import winreg unicode = str except ImportError: import _winreg as winreg # Python 2.x class Environment(object): path = r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment' hklm = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE) key = winreg.OpenKey(hklm, path, 0, winreg.KEY_READ | winreg.KEY_WRITE) SendMessage = ctypes.windll.user32.SendMessageW SendMessage.argtypes = HWND, UINT, WPARAM, LPVOID SendMessage.restype = LRESULT HWND_BROADCAST = 0xFFFF WM_SETTINGCHANGE = 0x1A NO_DEFAULT_PROVIDED = object() def get(self, name, default=NO_DEFAULT_PROVIDED): try: value = winreg.QueryValueEx(self.key, name)[0] except WindowsError: if default is self.NO_DEFAULT_PROVIDED: raise ValueError("No such registry key", name) value = default return value def set(self, name, value): if value: winreg.SetValueEx(self.key, name, 0, winreg.REG_EXPAND_SZ, value) else: winreg.DeleteValue(self.key, name) self.notify() def notify(self): self.SendMessage(self.HWND_BROADCAST, self.WM_SETTINGCHANGE, 0, u'Environment') Environment = Environment() # singletion - create instance PATH_VAR = 'PATH' def append_path_envvar(addpath): def canonical(path): path = unicode(path.upper().rstrip(os.sep)) return winreg.ExpandEnvironmentStrings(path) # Requires Python 2.6+ canpath = canonical(addpath) curpath = Environment.get(PATH_VAR, '') if not any(canpath == subpath for subpath in canonical(curpath).split(os.pathsep)): Environment.set(PATH_VAR, os.pathsep.join((curpath, addpath))) def remove_envvar_path(folder): """ Remove *all* paths in PATH_VAR that contain the folder path. """ curpath = Environment.get(PATH_VAR, '') folder = folder.upper() keepers = [subpath for subpath in curpath.split(os.pathsep) if folder not in subpath.upper()] Environment.set(PATH_VAR, os.pathsep.join(keepers)) 

示例用法：

 print(Environment.get('path')) append_path_envvar(r'C:\path\to\myprogram\dist') append_path_envvar(r'D:\another\path\to\myprogram\dist') print(Environment.get('path')) remove_envvar_path(r'\myprogram') # remove *both* added paths print(Environment.get('path')) 

我从你的问题的路径推断，你有兴趣在Windows平台上做这个。

文档描述了这个过程：

要以编程方式添加或修改系统环境变量，请将它们添加到HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Control \ Session Manager \ Environment注册表项中，然后广播一个WM_SETTINGCHANGE消息，并将lParam设置为字符串“Environment”。 这使应用程序（如shell）能够获取更新。

你应该检查os.environ 。 这是一个字典，可以直接操作或通过os.putenv ：

将名为varname的环境变量设置为字符串值。 这样的环境变化会影响以os.system（），popen（）或fork（）和execv（）开始的子进程。

因此：

 >>> import os >>> os.environ["PATH"] = path_old + ":/tmp/hallo" >>> os.environ["PATH"] '/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/bin/vendor_perl:/usr/bin/core_perl:/tmp/hallo' 

[更新]

根据这个答案，你可以使他们持久通过Windows注册表