# Python Dotenv Module

The `python-dotenv` library reads key-value pairs from a `.env` file and can set them as environment variables. It helps in the development of applications following the 12-factor principles.

## Installation

```bash
pip install python-dotenv
```

## Basic Usage

Create a `.env` file in your project root:

```text
API_KEY=your_api_key_here
DATABASE_URL=postgres://user:pass@localhost:5432/db
DEBUG=True
```

Then load it in your Python script:

```python
import os
from dotenv import load_dotenv

# Load environment variables from .env file
load_dotenv()

# Access variables
api_key = os.getenv("API_KEY")
database_url = os.getenv("DATABASE_URL")

print(f"API Key: {api_key}")
```

## Overriding System Variables

By default, `load_dotenv` does not override existing environment variables. To override them, use `override=True`.

```python
load_dotenv(override=True)
```

## Loading Specific Files

You can specify a path to a specific env file.

```python
from pathlib import Path
from dotenv import load_dotenv

env_path = Path('.') / '.env.dev'
load_dotenv(dotenv_path=env_path)
```

[[programming/python/python]]