Virtual Environment

The use of a Virtual Environment is to test python code in encapsulated environments, and to also avoid filling the base Python installation with libraries we might use for only one project.

venv

venv is the standard library module for creating virtual environments in Python 3.3+. It’s built into Python, so no installation is required.

1. Create a virtual environment

python -m venv venv

Or on some systems:

python3 -m venv venv

This creates a venv directory in your current folder containing the virtual environment.

2. Activate the virtual environment

On Linux/macOS:

source venv/bin/activate

On Windows:

venv\Scripts\activate

Once activated, you’ll see (venv) at the beginning of your command prompt, indicating the virtual environment is active.

3. Install packages

With the virtual environment activated, install packages using pip:

pip install package_name

Packages installed will be specific to this virtual environment.

4. Deactivate the virtual environment

To exit the virtual environment:

deactivate

The (venv) prefix will disappear from your command prompt.

virtualenv

1. Install virtualenv

pip install virtualenv

1. Install virtualenvwrapper-win (Windows)

pip install virtualenvwrapper-win

Usage:

1. Make a Virtual Environment named HelloWorld

mkvirtualenv HelloWorld

Anything we install now will be specific to this project. And available to the projects we connect to this environment.

1. Set Project Directory

To bind our virtualenv with our current working directory we simply enter:

setprojectdir .

1. Deactivate

To move onto something else in the command line type deactivate to deactivate your environment.

deactivate

Notice how the parenthesis disappear.

1. Workon

Open up the command prompt and type workon HelloWorld to activate the environment and move into your root project folder

workon HelloWorld

Poetry

1. Install Poetry

pip install --user poetry

2. Create a new project

poetry new my-project

This will create a my-project directory:

my-project
├── pyproject.toml
├── README.rst
├── poetry_demo
│   └── __init__.py
└── tests
    ├── __init__.py
    └── test_poetry_demo.py

The pyproject.toml file will orchestrate your project and its dependencies:

[tool.poetry]
name = "my-project"
version = "0.1.0"
description = ""
authors = ["your name <your@mail.com>"]

[tool.poetry.dependencies]
python = "*"

[tool.poetry.dev-dependencies]
pytest = "^3.4"

3. Packages

To add dependencies to your project, you can specify them in the tool.poetry.dependencies section:

[tool.poetry.dependencies]
pendulum = "^1.4"

Also, instead of modifying the pyproject.toml file by hand, you can use the add command and it will automatically find a suitable version constraint.

poetry add pendulum

To install the dependencies listed in the pyproject.toml:

poetry install

To remove dependencies:

poetry remove pendulum

For more information, check the documentation or read here:

• Python projects with Poetry and VSCode. Part 1
• Python projects with Poetry and VSCode. Part 2
• Python projects with Poetry and VSCode. Part 3

Pipenv

1. Install pipenv

pip install pipenv

2. Enter your Project directory and install the Packages for your project

cd my_project
pipenv install <package>

Pipenv will install your package and create a Pipfile for you in your project’s directory. The Pipfile is used to track which dependencies your project needs in case you need to re-install them.

3. Uninstall Packages

pipenv uninstall <package>

4. Activate the Virtual Environment associated with your Python project

pipenv shell

5. Exit the Virtual Environment

exit

Find more information and a video in docs.pipenv.org.

Anaconda

Usage:

1. Make a Virtual Environment

conda create -n HelloWorld

2. To use the Virtual Environment, activate it by:

conda activate HelloWorld

Anything installed now will be specific to the project HelloWorld

3. Exit the Virtual Environment

conda deactivate

UV

1. Install UV

# Using curl (Linux/macOS)
curl -LsSf https://astral.sh/uv/install.sh | sh

# Using pip or pipx
pip install uv

2. Create a new project with virtual environment

uv init my-project
cd my-project

3. Add dependencies

uv add requests

4. Run commands in project environment

uv run python script.py

5. Activate the virtual environment manually (optional)

source .venv/bin/activate  # Linux/macOS
.venv\Scripts\activate     # Windows

UV automatically manages virtual environments, Python versions, and dependencies with exceptional speed and convenience.

Relevant links

• Packaging
• Python projects with Poetry and VSCode. Part 1
• Python projects with Poetry and VSCode. Part 2
• Python projects with Poetry and VSCode. Part 3
• UV: The Lightning-Fast Python Package Manager
• import()