Cheat Sheets
Quick reference, when you need it
The syntax you reach for most, on a single page. Bookmark them, or keep one open next to your editor.
- SQLSQL Cheat SheetThe essential SQL statements on one page, from SELECT and WHERE to GROUP BY, JOINs and table changes.
- SQLSQL JOIN Cheat SheetEvery JOIN type with diagrams, syntax, and when to use each one.
- SQLSQL Functions Cheat SheetAggregate, string, date, and conditional functions with dialect differences.
- PythonPython Basics Cheat SheetVariables, types, operators, strings, conditions, loops, and functions at a glance.
- PythonPython Data Structures Cheat SheetLists, tuples, sets, and dictionaries with their most useful methods.
- PythonPython Functions Cheat SheetParameters, defaults, *args, **kwargs, lambdas, and scope rules.
- CC Cheat SheetTypes and format specifiers, strings, pointers, malloc and free, structs, files, the preprocessor and bit tricks on one page.
- C++C++ Basics Cheat SheetTypes, operators, input and output, strings, conditions, loops, and functions at a glance.
- C++C++ STL Cheat Sheetvector, string, map, set, unordered_map, stack, queue, and the most useful algorithms.
- C++C++ OOP and Memory Cheat SheetClasses, constructors, inheritance, virtual functions, references, pointers, smart pointers, and move semantics.
- JavaJava Basics Cheat SheetTypes, operators, strings, input and output, conditions, loops, arrays, and methods at a glance.
- JavaJava Collections and Streams Cheat SheetArrayList, HashMap, HashSet, queues, sorting with Comparator, and the most useful stream operations.
- JavaJava OOP Cheat SheetClasses, constructors, inheritance, interfaces, records, enums, exceptions, and generics.
- HTMLHTML Cheat SheetPage skeleton, text, links, images, lists, tables, forms, semantic layout, media and accessibility essentials.
- CSSCSS Cheat SheetSelectors, specificity, the box model, units, colours, text, display, position, responsive design, variables and animation.
- CSSCSS Flexbox and Grid Cheat SheetFlex containers and items, grid tracks, placement and template areas, centering, and common layout patterns.
- JavaScriptJavaScript Basics Cheat SheetVariables, types, strings, numbers, operators, conditions, loops, functions, errors, classes and modules at a glance.
- JavaScriptJavaScript Arrays and Objects Cheat SheetArray methods (map, filter, reduce, sort), objects, destructuring and spread, Map and Set, JSON and dates.
- JavaScriptJavaScript DOM and Async Cheat SheetSelecting and changing elements, events and delegation, forms, storage, timers, promises, async/await and fetch.
- TypeScriptTypeScript Cheat SheetTypes, interfaces, unions and narrowing, functions, classes, generics, utility and mapped types, assertions and tsconfig.
- ReactReact Cheat SheetJSX, components and props, conditions and lists, state updates, events and forms, effects, refs, reducers, context, custom hooks, performance, TypeScript, routing and testing.
- Node.js and ExpressNode.js and Express Cheat SheetRunning Node, modules, files and paths, process and events, streams and the event loop, Express routes, middleware and errors, status codes, validation, SQLite, auth, security and testing.
- DSAData Structures and Algorithms Cheat SheetBig O, Python structure costs, standard library tools, and templates for binary search, two pointers, BFS, DFS, Dijkstra and dynamic programming.
- Python for Datapandas and NumPy Cheat SheetLoading, inspecting, selecting, filtering, cleaning, grouping, pivoting, merging, dates, statistics and plotting with pandas and NumPy.
- Machine LearningMachine Learning Cheat SheetThe scikit-learn workflow, choosing a model, regression and classification metrics, pipelines, cross-validation and tuning, ensembles, clustering, PCA, text, saving models and the PyTorch training loop.
Printable PDF versions are planned for every cheat sheet.