Cleaning Up Environment Variables After卸载Python: Restoring System Environment Variables to Prevent Chaos After Uninstallation and Ensuring System Stability

# The Necessity and Impact of Uninstalling Python

Uninstalling Python may be necessary under certain circumstances, such as:

- **Upgrading Python versions:** Uninstalling the old version to install a new one.
- **Cleaning up the system:** Removing unused Python installations to free up disk space.
- **Solving problems:** Uninstalling Python may help resolve errors or issues related to the Python installation.

Uninstalling Python can have the following impacts on the system:

- **Cleaning up environment variables:** The uninstall process will delete environment variables related to Python, which may affect applications and scripts that use Python.
- **System commands unavailable:** Certain system commands (e.g., "python") rely on Python environment variables, and after uninstalling Python, these commands will become unavailable.
- **System chaos:** Incorrectly uninstalling Python could lead to system chaos, such as incorrect environment variable settings or system commands not being executable.

# Cleaning Environment Variables During Python Uninstall Process

### Types and Functions of Python Environment Variables

Python environment variables are divided into two types: system environment variables and user environment variables.

#### System Environment Variables

System environment variables are valid within the ***mon system environment variables include:

- `PATH`: Specifies the executable file search path.
- `PYTHONHOME`: Specifies the Python installation directory.
- `PYTHONPATH`: Specifies the Python module search path.

#### User Environment Variables

User environment variables are only valid for the current user. They are stored in the user'***mon user environment variables include:

- `USERPROFILE`: Specifies the user configuration file path.
- `APPDATA`: Specifies the user application data path.
- `LOCALAPPDATA`: Specifies the user local application data path.

### Cleaning Principles of Environment Variables During Python Uninstall

#### Overview of Cleaning Principles

When uninstalling Python, it is necessary to clean up environment variables related to Python. The cleaning principles are as follows:

- Delete all variables that point to the Python installation directory.
- Delete all variables that point to the Python module directory.
- Retain variables related to other applications.

#### Specific Methods of Cleaning

**Cleaning System Environment Variables**

# Open the Registry Editor
regedit

# Navigate to the following path:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

# Find and delete the following variables:
PYTHONHOME
PYTHONPATH

**Cleaning User Environment Variables**

# Open the user configuration file
%USERPROFILE%\.profile

# Find and delete the following variables:
PYTHONHOME
PYTHONPATH

**Code Logic Analysis:**

The above code searches for and deletes environment variables related to Python through the Registry Editor and user configuration files.

**Parameter Explanation:**

- `regedit`: Opens the Registry Editor.
- `%USERPROFILE%\.profile`: User configuration file path.

# Restoring Environment Variables After Python Uninstall

### Restoring System Environment Variables

#### Finding and Modifying Environment Variables

System environment variables are stored in the registry and can be found and modified by following these steps:

1. Open the Registry Editor (regedit.exe).
2. Navigate to the following path:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment