PYTHONPATH, Python 모듈 환경설정

In Python, an environment variable for a module or Python environment is a way to configure certain settings or provide data paths before running a Python program. Environment variables can be used to:

1. Control Python's runtime behavior (e.g., specifying paths for module search).
2. Pass configuration or sensitive data (like API keys) to Python applications.
3. Set up virtual environments for Python project isolation.

Here are some common environment variables related to Python and its modules:

1. PYTHONPATH:

• This variable defines the search path for modules. It allows you to specify additional directories for Python to look for modules and packages.

• If you want Python to find your custom modules, you can set this environment variable.

  Example:

  export PYTHONPATH="/path/to/your/module:$PYTHONPATH"
  

  In Windows:

  set PYTHONPATH=C:\path\to\your\module;%PYTHONPATH%
  

  This tells Python to also search for modules in /path/to/your/module.

2. PYTHONHOME:

• Specifies the location of the Python interpreter and standard library. It's used when you want to override the default Python installation and use a different one.
• Example:

  export PYTHONHOME="/custom/python/installation"
  

3. VIRTUAL_ENV:

• When you activate a virtual environment (via venv or virtualenv), this variable is automatically set to the path of the activated environment. It helps Python know which virtual environment is currently active.

4. PYTHONSTARTUP:

• If you set this variable, Python will execute the script it points to when starting an interactive shell. This can be useful for initializing certain behaviors or loading custom modules automatically.

  Example:

  export PYTHONSTARTUP="$HOME/.pythonrc.py"
  

5. PYTHONIOENCODING:

• This defines the encoding for input and output in Python. You can set it to control how Python handles text encoding (especially useful when dealing with non-UTF-8 environments).

  Example:

  export PYTHONIOENCODING="utf-8"
  

6. PYTHONHASHSEED:

• Python uses hash randomization to improve security. By setting this environment variable, you can control the seed value for hash randomization.

  Example:

  export PYTHONHASHSEED=0
  

7. PIP_CONFIG_FILE:

• Used to specify the location of the configuration file for pip, Python’s package manager. This allows you to override the default behavior of pip for installing and managing packages.

  Example:

  export PIP_CONFIG_FILE="/path/to/pip.conf"
  

8. DJANGO_SETTINGS_MODULE (for Django):

• In Django, you can set the environment variable DJANGO_SETTINGS_MODULE to specify the settings module for the Django project. This is useful when running Django applications in different environments (development, production).

  Example:

  export DJANGO_SETTINGS_MODULE="myproject.settings"
  

Setting Environment Variables

• On Linux/macOS: You can set environment variables in your terminal session using export:

  export VARIABLE_NAME=value
  

  To make these settings persistent, add the export lines to your ~/.bashrc or ~/.zshrc file.

• On Windows: Use the set command in the command prompt:

  set VARIABLE_NAME=value
  

  To make environment variables persistent, go to System Properties → Advanced → Environment Variables, and add them under User variables or System variables.

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These environment variables help control and manage Python module behaviors, virtual environments, and overall project configurations. Let me know if you need help with specific variables!