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#python (88)

Cheat sheets (88)

AWS CLI — Command-Line Interface for Amazon Web Services

Drive every AWS service from a terminal. Covers install (pip vs v2 installer), aws configure, profiles, SSO, day-to-day commands across S3 / EC2 / Lambda / IAM / STS, common scenarios, and credential precedence.
python aws cloud cli sdk

beets Music Organizer

Importing, tagging, querying, and organizing a music library with beets — config, plugins, queries, and common workflows on Windows.
beets windows music audio tagging library cli python web-researched

Claude API

The Anthropic Claude API — Python and TypeScript SDKs, streaming, tool use, batches, prompt caching, files, vision, and agentic loops.
claude anthropic api python typescript tool-use streaming batch caching files

Claude API — Python

Complete Python SDK reference for the Anthropic Claude API — messages, streaming, vision, extended thinking, prompt caching, batch processing, and token counting.
claude api anthropic python sdk streaming vision caching batch

DSPy — Programmatic Prompting and Optimisation

Build LLM programs in DSPy with declarative signatures, modules, and optimisers. Covers Predict, ChainOfThought, ReAct, BootstrapFewShot, COPRO, MIPRO, MIPROv2, and inference compilation.
python dspy llm ai prompting optimisation stanford signatures modules

Haystack 2.x — Pipelines for LLM Applications

Build production-grade LLM pipelines with Haystack 2.x. Covers components, the pipeline graph, indexing and querying, retrievers, generators, RAG patterns, and evaluation.
python haystack llm rag ai pipelines deepset retrievers generators

MCP Frameworks — Servers, Clients, and Transports

Model Context Protocol (MCP) framework overview. Covers client/server architecture, stdio vs SSE vs streamable HTTP transports, FastMCP, mcp-go, the Python and TypeScript SDKs, and comparison with custom tool servers.
mcp model-context-protocol anthropic python typescript go fastmcp tools sse stdio ai

Semantic Kernel — Microsoft's AI Orchestration SDK

Build LLM-powered applications with Microsoft Semantic Kernel. Covers the kernel, plugins, prompt templates, planners, function calling, Kernel Memory, Python and .NET SDKs.
python dotnet csharp semantic-kernel microsoft llm ai plugins planners memory

Pip Packages

Cheat sheets for third-party PyPI packages — HTTP clients, data tools, validation, terminal UIs, and more.
packages pip python pypi libraries

argparse — Stdlib CLI Argument Parser

Parse command-line arguments with Python's stdlib argparse module. Covers positional/optional args, subparsers, nargs, validation, mutually exclusive groups, FileType, env-var fallbacks, and argcomplete.
python stdlib cli scripting tooling

BeautifulSoup — HTML Parsing & Scraping

Parse, search, and mutate HTML/XML with BeautifulSoup 4. Covers parser choice (html.parser/lxml/html5lib), find/find_all/select, tree navigation, attribute access, and pairing with requests/httpx/playwright for end-to-end scraping.
python beautifulsoup scraping html parsing web

dataclasses — Boilerplate-Free Classes

Define typed data containers with @dataclass — frozen, slots, kw_only, default_factory, __post_init__, asdict, replace, and how it compares to attrs, pydantic, NamedTuple, TypedDict.
python stdlib typing

datetime — Dates, Times, Timezones

Work with dates, times, and timezones in Python using the stdlib datetime module and zoneinfo. Covers aware vs naive datetimes, ISO-8601 parsing, strftime/strptime, timedelta arithmetic, and DST handling.
python stdlib time timezones parsing data

Essential Python Packages

Overview of the 34 most useful Python packages — HTTP clients, data science, web frameworks, orchestration, testing, and tooling. Each has its own dedicated page with examples.
python packages pip overview

fastapi — Fast ASGI API Framework

Build high-performance async REST APIs with FastAPI. Covers path params, request bodies, Pydantic models, dependency injection, and auto-generated OpenAPI docs.
python fastapi api async asgi rest openapi pydantic

flask — Micro Web Framework

Build lightweight web apps and REST APIs with Flask. Covers routes, request handling, JSON responses, blueprints, and the debug-server warning.
python flask web api wsgi microframework

httpx — Modern HTTP Client

Make sync and async HTTP requests with httpx. Covers GET/POST, async usage, HTTP/2, streaming, and how it compares to requests.
python httpx http api async networking

Python Installation — Quick-Pick

Choose your OS and get Python installed in minutes. Covers Windows, WSL/Ubuntu, macOS, and Linux with recommended versions and verification steps.
python install

Python Installation — Linux

Install Python 3 on Debian/Ubuntu, Fedora/RHEL, and Arch Linux. Covers package managers, pyenv, and building from source for unsupported distros.
python install linux debian ubuntu fedora arch pyenv

Python Installation — macOS

Install Python 3 on macOS via Homebrew or pyenv. Explains the system-Python warning, PATH precedence, and verification steps.
python install macos homebrew pyenv

Python Installation — Windows

Install Python 3 on Windows via winget or the python.org installer. Covers PATH setup, the py launcher, and verification steps.
python install windows

Python Installation — WSL Ubuntu

Install Python 3 inside WSL2/Ubuntu via apt, the deadsnakes PPA, or pyenv. Covers the python3-venv quirk and version aliasing.
python install wsl ubuntu linux

itertools & functools — Functional Toolbelt

The two stdlib modules every Python developer pairs together — iterator algebra (chain, groupby, batched, pairwise) and function plumbing (lru_cache, partial, reduce, singledispatch, cached_property).
python stdlib functional itertools functools

json — Stdlib JSON Encoder/Decoder

Encode and decode JSON in Python with the stdlib json module. Covers dumps/loads, indent/sort_keys/separators, custom default= and JSONEncoder, object_hook decoding, JSONL streaming, and orjson/ujson/msgspec comparison.
python stdlib json data serialization parsing

logging — Stdlib Logging

Configure Python's built-in logging module — loggers, handlers, formatters, dictConfig, rotation, structured records, and how it compares to loguru.
python stdlib logging

pdb — Python Debugger

Pause, inspect, and step through Python programs with pdb. Covers breakpoint(), command reference, post-mortem debugging, conditional breakpoints, and enhanced alternatives like ipdb, pdbpp, and pudb.
python pdb debugging stdlib repl tooling

pip vs uv — Package Manager Comparison

Side-by-side feature comparison of pip and uv — speed, lock files, virtual envs, Python version management, and when to use each.
python package-management pip uv

poetry — Dependency Management & Packaging

Manage Python project dependencies, virtual environments, and package publishing with Poetry. Covers pyproject.toml, lockfiles, groups, and publishing to PyPI.
python poetry packaging dependencies pyproject lockfile

pre-commit — Git Hooks for Linters and Formatters

Run linters, formatters, and validators automatically on every git commit. Covers .pre-commit-config.yaml, essential hooks (ruff, mypy, check-yaml), autoupdate, and CI integration.
python pre-commit git-hooks workflow ci code-quality tooling

pydantic — Data Validation

Validate and parse data at runtime using Python type hints with Pydantic v2. Covers BaseModel, field validators, nested models, and JSON serialization.
python pydantic validation types models serialization

pyproject.toml — Modern Python Project Config

The canonical config file for modern Python projects — [project] metadata, [build-system] backends (setuptools, hatchling, pdm-backend, poetry-core, flit-core), [tool.*] sections, dynamic versioning, scripts, building, and publishing.
python packaging pyproject toml build pep-621

re — Python Regular Expressions

Python's built-in regex module — compile vs not, match/search/findall/finditer/sub, named groups, lookarounds, verbose mode (re.X), and how it differs from PCRE.
python stdlib regex re patterns

requests — HTTP for Humans

Make HTTP requests in Python with the requests library. Covers GET/POST, JSON, sessions, authentication, retries, and common pitfalls.
python requests http api networking

scikit-learn — Classical Machine Learning

Build classical ML pipelines with scikit-learn. Covers the estimator API, train_test_split, Pipeline, ColumnTransformer, cross-validation, metrics, and model persistence.
python scikit-learn ml data-science pipelines modeling classification

streamlit — Data Apps in Pure Python

Build interactive web apps for data and ML in pure Python. Covers widgets, layout, session state, caching, multipage apps, and deployment patterns.
python streamlit ui dataviz prototyping web frontend

subprocess — Spawning Processes

Run external commands from Python with subprocess. Covers run vs Popen, capture_output, streaming, pipes, timeouts, env/cwd overrides, and shlex quoting safety.
python stdlib shell

typing — Advanced Type Hints

Go beyond list[int] and str | None. Covers Protocol, TypeVar bounds, ParamSpec, Concatenate, Self, Annotated, TypedDict with NotRequired/Required, TypeAlias, TypeGuard, TypeIs, cast, assert_type, and reveal_type.
python typing types stdlib mypy generics protocol

uv — Fast Python Package Manager

Install packages and manage virtual environments blazingly fast with uv. Covers uv pip, uv venv, uv run, uv init, and how it compares to pip and poetry.
python uv pip packaging venv tools astral

Virtual Environments — venv

Create, activate, and manage Python virtual environments with venv. Covers activation for every shell, pip usage, requirements files, and cleanup.
python venv virtualenv pip packaging

Sentence Transformers — Embeddings, Search & Fine-Tuning

Comprehensive reference for the sentence-transformers Python library — embeddings, similarity, clustering, retrieval, fine-tuning, and popular models (BGE, E5, GTE, Nomic, Jina).
python embeddings nlp sentence-transformers semantic-search vector-db rag clustering fine-tuning bge e5 gte nomic jina

Frameworks

Hugging Face Transformers, LangChain, Google Gemini SDK, and LangSmith — practical reference for AI/ML frameworks and observability tools.
ai llm python ml transformers langchain gemini

AutoGen — Multi-Agent Conversations

Build multi-agent AI systems with Microsoft AutoGen. Covers agents, group chats, code execution, tool registration, async runtimes, and LLM configuration.
python autogen agents llm ai microsoft multi-agent code-execution

ChromaDB — Embedded Vector Database

Store and query vector embeddings locally or over a network with ChromaDB. Covers client types, collections, add, query, metadata filters, embedding functions, and LangChain/LlamaIndex integration.
python chromadb vector-database embeddings rag ai similarity-search

crewAI — Role-Based Agent Crews

Orchestrate teams of role-playing AI agents with crewAI. Covers agents, tasks, crews, tools, LLM selection, memory, YAML config, and the kickoff lifecycle.
python crewai agents llm ai multi-agent rag tools

google-generativeai — Gemini SDK

Call Google's Gemini models from Python for text, multimodal, streaming, chat, function calling, and embeddings. Covers the genai SDK, safety settings, file API, and async usage.
python google gemini llm ai multimodal api

guidance — Constrained LLM Generation

Interleave Python control flow with LLM generation and enforce structured output using guidance. Covers gen(), select(), chat blocks, regex constraints, JSON schemas, and token healing.
python guidance llm ai structured-output constrained-generation transformers

LangChain — LLM Application Framework

Build LLM-powered pipelines with LangChain. Covers LCEL chains, chat models, prompts, output parsers, tools, agents, retrievers, memory, and streaming.
python langchain llm ai rag agents openai anthropic

LangSmith — LLM Observability & Evaluation

Trace, debug, evaluate, and monitor LLM applications with LangSmith. Covers tracing setup, datasets, evaluators, prompt hub, comparing runs, and CI integration.
python langsmith llm observability tracing evaluation langchain ai

LlamaIndex — Data Framework for LLMs

Build RAG pipelines and LLM-powered data applications with LlamaIndex. Covers document loading, indexing, query engines, custom LLMs and embeddings, persistent storage, and agents.
python llamaindex llm rag ai embeddings agents retrieval

notebooklm-py — Unofficial NotebookLM Client

Automate Google NotebookLM from Python with the unofficial notebooklm-py library. Covers authentication, notebook and source management, summaries, FAQ generation, and audio podcast creation.
python notebooklm google ai automation unofficial

qdrant-client — High-Performance Vector Database

Store and search vector embeddings with the Qdrant Python client. Covers collections, CRUD, filtered vector search, payload indexing, batch upsert, sparse/dense hybrid search, and integrations.
python qdrant vector-database embeddings rag search ai

ragas — RAG Evaluation Framework

Measure and improve RAG pipeline quality with ragas. Covers faithfulness, answer relevancy, context precision, context recall, dataset format, LLM judges, and CI integration.
python ragas rag evaluation llm ai retrieval metrics

transformers — Hugging Face

Load and run pre-trained models for NLP, vision, and audio with the Hugging Face Transformers library. Covers pipelines, AutoModel, tokenisation, generation, fine-tuning, and device placement.
python huggingface transformers llm nlp ml pytorch

TruLens — LLM App Evaluation

Evaluate and monitor LLM applications with TruLens. Covers the RAG triad, feedback functions, TruChain, TruLlama, custom evaluators, the dashboard, and CI integration.
python trulens rag evaluation llm ai observability feedback

unstructured — Document Parsing & Ingestion

Extract structured text from PDFs, Word docs, HTML, images, and more with the unstructured library. Covers partitioning, chunking, cleaning, metadata, and pipeline integrations.
python unstructured pdf parsing ingestion rag document etl

weaviate-client — Vector Database Client

Store, search, and manage vector embeddings with the Weaviate Python client. Covers collections, CRUD, vector/hybrid/BM25 search, multi-tenancy, generative search, and batch import.
python weaviate vector-database embeddings rag search ai

dagster — Modern Data Orchestration

Build, schedule, and observe data pipelines as software-defined assets with Dagster. Covers assets, jobs, schedules, sensors, resources, partitions, and the Dagster UI.
python dagster orchestration data pipelines assets etl mlops

DuckDB — Embedded Analytics Database

Run fast analytical SQL queries in-process with DuckDB. Covers Python API, CSV/Parquet ingestion, pandas interop, Arrow, window functions, and persistent databases.
python duckdb sql analytics olap parquet pandas arrow

litestar — High-Performance ASGI Framework

Build fast, type-safe HTTP APIs and web apps with Litestar. Covers route handlers, path/query/body params, DTOs, dependency injection, middleware, WebSockets, and OpenAPI.
python litestar asgi api web fastapi openapi rest

modin — Drop-in pandas at Scale

Speed up pandas workloads across all CPU cores with a one-line import swap. Covers Ray and Dask backends, config tuning, pandas interop, and when modin wins vs polars.
python modin pandas dataframes parallel ray dask data

polars — Fast DataFrames

High-performance DataFrames with a lazy expression API. Covers read/write, select, filter, group_by, joins, LazyFrame, datetime, string operations, and pandas interop.
python polars dataframes data csv parquet sql

prefect — Workflow Orchestration

Build, schedule, and observe Python workflows with Prefect. Covers flows, tasks, retries, schedules, deployments, caching, concurrency, and Prefect Cloud.
python prefect orchestration workflows scheduling etl pipelines

reflex — Full-Stack Web Apps in Pure Python

Build interactive web applications entirely in Python with Reflex. Covers state, components, events, pages, database, forms, and deployment.
python reflex web fullstack react ui components state

SQLModel — Typed ORM for FastAPI

Define database models with Python type hints using SQLModel. Covers table creation, CRUD, relationships, FastAPI integration, Pydantic validation, and async sessions.
python sqlmodel orm sql fastapi pydantic sqlalchemy database

tqdm — Progress Bars

Add auto-updating progress bars to any Python loop or CLI pipeline with tqdm. Covers iterables, manual updates, pandas integration, nested bars, async, Jupyter, and byte-piping.
python tqdm progress cli jupyter async

typer — CLI Apps with Type Hints

Build command-line interfaces using Python type annotations with Typer. Covers commands, options, arguments, subcommands, callbacks, rich output, and testing.
python typer cli argparse click terminal

Programming

A reference hub for programming languages and their ecosystems — Python, JavaScript, and TypeScript, with package managers, runtimes, and tooling.
programming python javascript typescript overview

pip — Python Package Installer

Complete pip reference covering installation, package management, requirements files, private registries, caching, offline installs, and reproducible builds.
python pip packages cli packaging

Python

Installation guides, essential packages, CLI snippets, and real-world recipes for Python 3.
python overview

asyncio — Async I/O

Write concurrent Python code with asyncio. Covers coroutines, asyncio.run, gather, create_task, timeouts, queues, and avoiding the blocking-call pitfall.
python asyncio async await concurrency coroutines

black — Python Code Formatter

Format Python code consistently with black. Covers installation, configuration, editor integration, and how it compares to ruff format.
python black formatting code-quality tools

Python CLI Snippets

Short standalone Python scripts for common tasks — file I/O, JSON manipulation, HTTP requests, CSV processing, and data transformation.
python snippets cli scripts json csv http file-io

click — CLI Builder

Build command-line interfaces with click using decorators. Covers commands, options, arguments, groups, prompts, and progress bars.
python click cli argparse terminal commands

django — Full-Stack Web Framework

Build database-driven web applications with Django. Covers project setup, models, migrations, the admin panel, views, forms, class-based views, middleware, signals, ORM advanced patterns, and the management command workflow.
python django web orm wsgi framework admin

jupyter — Interactive Notebooks

Run interactive Python notebooks with Jupyter. Covers JupyterLab setup, cell types, keyboard shortcuts, magic commands, nbconvert export, and common pitfalls.
python jupyter notebooks data analysis interactive

loguru — Structured Logging

Add structured, colorized logging to Python apps with loguru. Covers sinks, log levels, file rotation, retention, exception catching, and context binding.
python loguru logging debugging structured-logging

matplotlib — Plotting

Create publication-quality 2-D plots with matplotlib. Covers pyplot basics, subplots, savefig, common chart types, and the show-vs-save pitfall.
python matplotlib plotting visualization charts graphs

mypy — Static Type Checker

Catch type errors before runtime with mypy. Covers strict mode, common error codes, type: ignore annotations, gradual typing, and pyproject.toml configuration.
python mypy typing types static-analysis type-hints

numpy — Numerical Arrays

Create and manipulate N-dimensional arrays with NumPy. Covers array creation, broadcasting, vectorized math, indexing, and matrix operations.
python numpy arrays math data scientific

Python One-Liners

Useful Python one-liners runnable directly from the shell with python -c or python -m. No file creation needed.
python oneliners cli shell snippets

pandas — DataFrames

Load, filter, transform, and aggregate tabular data with pandas. Covers DataFrame creation, read_csv, groupby, merge, and the SettingWithCopy pitfall.
python pandas dataframes data csv analysis

pathlib — Object-Oriented File Paths

Work with filesystem paths using Python's built-in pathlib module. Covers Path creation, navigation, reading/writing files, glob patterns, and stat.
python pathlib files filesystem stdlib paths

Pillow — Image Processing

Open, resize, crop, convert, and save images with Pillow (PIL fork). Covers format conversion, filters, drawing, and EXIF handling.
python pillow pil images imaging graphics

pytest — Testing Framework

Write and run Python tests with pytest. Covers test discovery, assertions, fixtures, parametrize, conftest, and common patterns.
python pytest testing fixtures parametrize tdd

rich — Beautiful Terminal Output

Make terminal output beautiful with Rich. Covers styled print, Console, tables, progress bars, syntax highlighting, live displays, and the rich-cli command.
python rich terminal tui cli colors progress tables

ruff — Fast Linter & Formatter

Lint and format Python code with ruff — a single Rust-powered tool that replaces flake8, isort, and black. Covers configuration, rule selection, and CI usage.
python ruff linting formatting code-quality tools

scipy — Scientific Computing

Statistical distributions, optimization, integration, signal processing, and linear algebra with SciPy. Builds on NumPy arrays.
python scipy statistics optimization scientific math

sqlalchemy — SQL Toolkit & ORM

Connect to databases, write queries, and define ORM models with SQLAlchemy 2.0. Covers the engine, sessions, Core queries, ORM declarative models, relationships, session lifecycle, migrations with Alembic, and connection pool configuration.
python sqlalchemy orm sql database sqlite postgres