How do I manage virtual environments in Python?

Managing virtual environments in Python is essential for isolating project dependencies and ensuring that different projects do not interfere with each other. The recommended way to create and manage virtual environments depends on your workflow and tools, but here are the most common and effective methods: ### Using `venv` (Built-in in Python 3.3+) Python’s standard library includes the `venv` module, which allows you to create lightweight virtual environments without installing anything extra. This is the simplest and most widely used approach. To create a virtual environment, run: ```bash python3 -m venv myenv ``` Here, `myenv` is the directory where the environment will be created. To activate the environment: - On Windows (PowerShell): ```powershell .\myenv\Scripts\Activate.ps1 ``` - On Windows (Command Prompt): ```cmd myenv\Scripts\activate.bat ``` - On macOS/Linux: ```bash source myenv/bin/activate ``` Once activated, you can install packages using `pip` and they will be isolated from the global Python installation. To deactivate the environment, simply run: ```bash deactivate ``` ### Using `virtualenv` `virtualenv` is a popular third-party tool that predates `venv` and offers some additional features and supports older Python versions. It’s installed via pip: ```bash pip install virtualenv ``` Then create an environment with: ```bash virtualenv myenv ``` Activation and deactivation are the same as with `venv`. ### Using `pipenv` `pipenv` aims to combine `pip` and virtual environment management into a single tool. It automatically creates and manages virtual environments for your projects and adds/removes packages from a `Pipfile` to keep track of dependencies. Install it with: ```bash pip install pipenv ``` To create a virtual environment and install packages: ```bash pipenv install requests ``` To activate the environment shell: ```bash pipenv shell ``` `pipenv` is useful for simplifying dependency management and ensuring reproducible environments. ### Using `poetry` `poetry` is another modern tool that manages dependencies and virtual environments. It provides a more opinionated and streamlined workflow for Python projects. Install it following instructions at [https://python-poetry.org/](https://python-poetry.org/). Create a project and manage dependencies easily: ```bash poetry init poetry add requests poetry shell ``` --- ### Summary - For most users, **`venv`** is the recommended and simplest built-in way to manage virtual environments. - Use **`pipenv`** or **`poetry`** if you want more automated dependency and environment management integrated into your workflow. - Always activate the virtual environment before installing or running your project’s Python code. - Keep each project’s environment separate to avoid dependency conflicts. By using virtual environments, you maintain clean, reproducible, and isolated project setups, which is a best practice in Python development.