Python

What are poetry and uv, why are they useful

Both are Python package managers that handle dependency resolution, lockfiles, and virtual environment creation.

What are the basic commands to start a new python project with uv

uv init project-name — scaffold a new project with pyproject.toml

uv add requests — add a dependency

uv remove requests — remove a dependency

uv sync — install all deps from lockfile

uv run main.py — run a script in the managed environment

What are common uv commands when working on projects?

uv add --dev pytest — add a dev dependency
uv sync — install/update all deps from lockfile

uv run command — run any command in the project environment (without you needing to manually activate it.) not needed if venv already active

uv lock — regenerate the lockfile without installing

uv tree — show dependency tree

What's the difference between carrot and tilde in package versions

Caret (^2.31.0): Allows changes that don't modify the leftmost non-zero digit. ^2.31.0 → ≥2.31.0, <3.0.0. (Poetry's default)

Tilde (~=2.31.0): Allows only patch-level changes. ~=2.31.0 → ≥2.31.0, <2.32.0.

In short: Caret is more permissive (any minor/patch bump), tilde is stricter (patch bumps only).

Semantic Versioning (SemVer): MAJOR.MINOR.PATCH

MAJOR (2.x.x) — breaking/incompatible API changes

MINOR (x.31.x) — new features, backwards compatible

PATCH (x.x.5) — bug fixes, backwards compatible

Why should we use a new virtual environment for every project?

Dependency isolation — different projects may need different versions of the same package. Without separate envs, they conflict.

Reproducibility — each project has only its own dependencies, making it easy to generate accurate lockfiles and replicate the setup elsewhere.

Clean uninstall — delete the env and everything's gone. No leftover packages polluting other projects or the system Python.

What does scaffolding mean?

Scaffolding = the automatic generation of a basic project structure or boilerplate code to help you start development faster.

It typically creates things like:

• folders and files

• starter code

• default configuration

• basic CRUD pages or routes

What is the init.py file?

__init__.py marks a directory as a Python package so that python treats it as such, so Python can import modules from it.

It can also run package initialization code when the package is imported.