What is UV?

  • An fast python package manager and project manager (Written in Rust)
  • replaces pip, pyvenv, virtualenv etc.
  • Runs scripts
  • Installs and Manages Python versions

Installation

  • UV can be installed using any one of the package managers (homebrew, pacman etc)

Commands

Initializing a project

uv init <project_name>
  • The above command creates a folder named <project_name>. Inside the project name there is a complete project directory including the virtual environment. UV expects you to follow this project structure.
    • Project Structure:
.
├── .venv
│   ├── bin
│   ├── lib
│   └── pyvenv.cfg
├── .python-version
├── README.md
├── main.py
├── pyproject.toml
└── uv.lock

pyproject.toml

  • This file contains the metadata about the project in question, that can either be added manually by editing this file or by running certain commands. Sample file:

  [project]
name = "hello-world"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
dependencies = []

Adding dependencies to the project

uv add request #package versions can be specified

Removing dependencies from the project

uv remove request

Running a program and running a script

#program
uv add flask
uv run --flask run -p 3000
#script
uv run <python_file_name>

Updating the environment

uv sync

Note: UV does not activate virtual environment using these command. One needs to activate the virtual environment first before running scripts or programs.

Creating virtual environment using uv

uv venv #creates .venv
uv venv <venv_name> #creates virtual environment named venv_name

Integration with emacs

Instructions

  • UV Mode works automatically once installed. Simply open a Python file in a project that has a .venv directory, and UV Mode will activate the appropriate virtual environment.