A complete reference to the Kotlin Standard Library String functions — creation and templates, inspection, comparison, searching, transformation, splitting, joining, type conversion, formatting, StringBuilder, CharSequence, and the most useful extension functions.
A complete reference to the Kotlin Standard Library IO functions — File extension functions, reading and writing text and bytes, forEachLine, useLines, bufferedReader and bufferedWriter, copyTo, walk, the Path API, InputStream and OutputStream, serialization, and IO error handling.
A complete reference to the Kotlin Standard Library Math functions — kotlin.math, mathematical constants, basic abs and sign functions, rounding, exponents and logarithms, trigonometry, min and max, bit operations, Random, BigDecimal for finance, and numeric extension functions.
A complete guide to Kotlin Collections — the difference between mutable and immutable, transformation operations like map and filter, grouping with groupBy, aggregation operations, and idiomatic usage in production code.
A complete guide to Kotlin Scope Functions — the differences between let, run, with, apply, and also, when to use each, idiomatic patterns in production code, and anti-patterns to avoid.
A complete guide to Kotlin Ranges and Progressions — the .., until, downTo, and step operators, usage in loops and when expressions, ranges on non-numeric types, custom progressions, and idiomatic patterns for validation and iteration.
A complete guide to Kotlin Higher-Order Functions — function types, lambda expressions, anonymous functions, inline functions, functions as parameters and return values, closures, and idiomatic functional programming patterns in production code.
A complete guide to Kotlin Type Conversion — explicit numeric conversion, safe casting with as?, String to number conversion with toIntOrNull, smart casts, collection conversions, and idiomatic patterns for avoiding ClassCastException.
A complete guide to Kotlin Numbers — numeric types and their capacities, arithmetic operations, BigDecimal for high precision, mathematical functions, number formatting, unsigned integers, and idiomatic patterns for financial and scientific calculations.
A complete guide to Kotlin Characters — the Char type and its representation, character classification with isDigit and isLetter, case conversion, arithmetic operations on Char, parsing and input validation, Unicode and special characters, and idiomatic patterns for character-level text processing.
A complete guide to Kotlin Sequences — the difference between eager and lazy evaluation, how to create sequences, terminal and intermediate operations, performance compared to Collections, generateSequence, the sequence builder, and when to switch from Collection to Sequence.
A complete guide to Kotlin Result — runCatching for catching exceptions, getOrElse and getOrDefault for fallback values, fold for handling success and failure, onSuccess and onFailure, Result composition, and idiomatic error handling patterns without verbose try-catch blocks.
A complete guide to Kotlin Enums — basic declarations, enums with properties and methods, interface implementations, sealed classes as an alternative, the built-in entries and valueOf operations, usage in when expressions, and idiomatic patterns for modeling state and structured constants.
A complete guide to Kotlin Comparator and Sorting — sortedBy and sortedWith, compareBy for multi-criteria, Comparable vs Comparator, thenBy for layered sorting, naturalOrder and reverseOrder, and idiomatic patterns for sorting complex objects in production code.
A complete guide to Kotlin Random — kotlin.random.Random vs java.util.Random, seeds for reproducibility, nextInt, nextDouble, nextBoolean, shuffle, sampling from collections, random with custom distributions, and idiomatic patterns for testing and simulation.
A complete guide to Kotlin Duration — representing time durations, conversion between units, measureTime and measureTimedValue for benchmarking, arithmetic operations on Duration, formatting, timeouts in coroutines, and idiomatic patterns for performance measurement and time management.
A complete guide to Kotlin Datetime with kotlinx-datetime — LocalDate, LocalTime, LocalDateTime, Instant, TimeZone, date arithmetic, formatting and parsing, timezone conversions, and idiomatic patterns for applications that handle time correctly.
A complete guide to Kotlin Reflection — KClass, KProperty, KFunction, runtime type introspection, function references, annotation usage, real use cases like lightweight serialization and simple dependency injection, and when reflection should be avoided.