Guides to Kotlin Built-in Functions

Here, you find a list of Kotlin functions from different packages. Each Kotlin function is explained with examples, output, and real-world use cases.

Kotlin Any Type Functions

• Kotlin Any equals Function
• Kotlin Any hashCode
• Kotlin Any toString

Kotlin Array Functions

• Kotlin arrayOf
• Kotlin emptyArray Function
• Kotlin Array Function
• Kotlin Array get Function
• Kotlin Array set Function
• Kotlin Array size Property
• Kotlin Array isEmpty Function
• Kotlin Array isNotEmpty Function
• Kotlin Array map Function
• Kotlin Array filter Function
• Kotlin Array forEach Function
• Kotlin Array sorted Function
• Kotlin Array sortedBy Function
• Kotlin Array sort Function
• Kotlin Array sortBy Function
• Kotlin Array sortDescending Function
• Kotlin Array sortByDescending Function
• Kotlin Array reduce Function
• Kotlin Array fold Function
• Kotlin Array reduceIndexed Function
• Kotlin Array reduceRight Function
• Kotlin Array foldRight Function
• Kotlin Array indexOf Function
• Kotlin Array lastIndexOf Function
• Kotlin Array contains Function
• Kotlin Array find Function
• Kotlin Array findLast Function
• Kotlin Array copyOf Function
• Kotlin Array copyOfRange Function
• Kotlin Array copyInto Function
• Kotlin Array joinToString Function
• Kotlin Array reverse Function
• Kotlin Array slice Function
• Kotlin Array plus Function
• Kotlin Array asList Function
• Kotlin Array contentDeepEquals Function
• Kotlin Array count Function
• Kotlin Array distinct Function
• Kotlin Array first Function
• Kotlin Array last Function
• Kotlin Array toList Function
• Kotlin Array toSet Function

Kotlin String Functions

• Kotlin String length Property
• Kotlin String get Function
• Kotlin String isEmpty Function
• Kotlin String isNotEmpty Function
• Kotlin String isBlank Function
• Kotlin String isNotBlank Function
• Kotlin String substring Function
• Kotlin String split Function
• Kotlin String trim Function
• Kotlin String trimStart Function
• Kotlin String trimEnd Function
• Kotlin String contains Function
• Kotlin String replace Function
• Kotlin String replaceFirst Function
• Kotlin String endsWith Function
• Kotlin String capitalize Function
• Kotlin String decapitalize Function
• Kotlin String toCharArray Function
• Kotlin String toByteArray Function
• Kotlin String plus Function
• Kotlin String compareTo Function
• Kotlin String repeat Function
• Kotlin String indexOf Function
• Kotlin String lastIndexOf Function
• Kotlin String indexOfFirst Function
• Kotlin String indexOfLast Function
• Kotlin String subSequence Function
• Kotlin String getOrNull Function
• Kotlin String getOrElse Function
• Kotlin String matches Function
• Kotlin String toRegex Function
• Kotlin String sorted Function
• Kotlin String map Function
• Kotlin String forEach Function
• Kotlin String filter Function
• Kotlin String sortDescending Function
• Kotlin String reduce Function
• Kotlin String fold Function

Kotlin List Functions

• Kotlin List last Function
• Kotlin MutableList reverse Function
• Kotlin List plus Function
• Kotlin Boolean equals Function
• Kotlin Boolean compareTo Function
• Kotlin Boolean toString Function
• Kotlin Boolean and Function
• Kotlin Boolean or Function
• Kotlin Boolean not Function
• Kotlin Boolean xor Function
• Kotlin listOf Function
• Kotlin mutableListOf Function
• Kotlin arrayListOf Function
• Kotlin emptyList Function
• Kotlin listOfNotNull Function
• Kotlin List asReversed Function
• Kotlin List binarySearch Function
• Kotlin List binarySearch Function
• Kotlin List getOrNull Function
• Kotlin List getOrElse Function
• Kotlin List subList Function
• Kotlin setOf Function
• Kotlin mutableSetOf Function
• Kotlin hashSetOf Function
• Kotlin emptySet Function
• Kotlin setOfNotNull Function
• Kotlin setOfNotNull Function
• Kotlin mapOf Function
• Kotlin mutableMapOf Function
• Kotlin hashMapOf Function
• Kotlin linkedMapOf Function
• Kotlin emptyMap Function
• Kotlin mapOfNotNull Function
• Kotlin mapOfNotNull Function
• Kotlin collectionSizeOrDefault Function
• Kotlin asIterable Function
• Kotlin asSequence Function
• Kotlin filter Function
• Kotlin filter Function
• Kotlin filterNot Function
• Kotlin filterNotNull Function
• Kotlin filterTo Function
• Kotlin List mapNotNull Function
• Kotlin mapTo Function
• Kotlin List flatMap Function
• Kotlin List flatMapTo Function
• Kotlin List groupBy Function
• Kotlin List groupByTo Function
• Kotlin List partition Function
• Kotlin List reduce Function

Kotlin ArrayList Functions

• Kotlin ArrayList add Function
• Kotlin ArrayList addAll Function
• Kotlin ArrayList clear Function
• Kotlin ArrayList contains Function
• Kotlin ArrayList containsAll Function
• Kotlin ArrayList equals Function
• Kotlin ArrayList get Function
• Kotlin ArrayList indexOf Function
• Kotlin ArrayList isEmpty Function
• Kotlin ArrayList iterator Function
• Kotlin ArrayList lastIndexOf Function
• Kotlin ArrayList remove Function
• Kotlin ArrayList removeAll Function
• Kotlin ArrayList set Function
• Kotlin ArrayList subList Function
• Kotlin ArrayList toArray Function

Kotlin HashMap Functions

• Kotlin HashMap clear Function
• Kotlin HashMap containsKey Function
• Kotlin HashMap containsValue Function
• Kotlin HashMap get Function
• Kotlin HashMap isEmpty Function
• Kotlin HashMap put Function
• Kotlin HashMap putAll Function
• Kotlin HashMap remove Function
• Kotlin HashSet add Function
• Kotlin HashSet addAll Function
• Kotlin HashSet clear Function
• Kotlin HashSet contains Function
• Kotlin HashSet remove Function
• Kotlin HashSet removeAll Function

Kotlin LinkedHashMap Functions

• Kotlin LinkedHashMap clear Function
• Kotlin LinkedHashMap containsKey Function
• Kotlin LinkedHashMap containsValue Function
• Kotlin LinkedHashMap get Function
• Kotlin LinkedHashMap put Function
• Kotlin LinkedHashMap putAll Function
• Kotlin LinkedHashMap remove Function
• Kotlin LinkedHashSet add Function
• Kotlin LinkedHashSet addAll Function
• Kotlin LinkedHashSet clear Function
• Kotlin LinkedHashSet contains Function
• Kotlin LinkedHashSet containsAll Function

Kotlin Sequence Functions

• Kotlin Sequence asSequence Function
• Kotlin Sequence map Function
• Kotlin Sequence filter Function
• Kotlin Sequence flatMap Function
• Kotlin Sequence toList Function
• Kotlin Sequence generateSequence Function
• Kotlin Sequence sequenceOf Function
• Kotlin Sequence sorted Function
• Kotlin Sequence sortedBy Function
• Kotlin Sequence sortedByDescending Function
• Kotlin Sequence sortedWith Function
• Kotlin Sequence distinct Function
• Kotlin Sequence distinctBy Function
• Kotlin Sequence take Function
• Kotlin Sequence takeWhile Function
• Kotlin Sequence drop Function
• Kotlin Sequence dropWhile Function
• Kotlin Sequence toSet Function
• Kotlin Sequence toMutableList Function
• Kotlin Sequence associate Function
• Kotlin Sequence associateBy Function
• Kotlin Sequence groupBy Function
• Kotlin Sequence partition Function
• Kotlin Sequence plus Function
• Kotlin Sequence filterNot Function
• Kotlin Sequence reduce Function
• Kotlin Sequence count Function
• Kotlin Sequence fold Function
• Kotlin Sequence sumBy Function
• Kotlin Sequence average Function
• Kotlin Sequence max Function
• Kotlin Sequence maxBy Function
• Kotlin Sequence min Function
• Kotlin Sequence first Function
• Kotlin Sequence last Function
• Kotlin Sequence single Function
• Kotlin Sequence all Function
• Kotlin Sequence any Function
• Kotlin Sequence indexOf Function
• Kotlin Sequence elementAt Function
• Kotlin Sequence elementAtOrElse Function
• Kotlin Sequence toHashSet Function
• Kotlin Sequence toSortedSet Function
• Kotlin Sequence toCollection Function
• Kotlin Sequence toMutableSet Function
• Kotlin Sequence toMap Function
• Kotlin Sequence toSortedMap Function
• Kotlin Sequence toMutableMap Function
• Kotlin Sequence joinToString Function
• Kotlin Sequence toArray Function
• Kotlin Sequence forEach Function
• Kotlin exitProcess Function
• Kotlin getTimeNanos Function
• Kotlin getTimeMillis Function
• Kotlin measureTimeMillis Function
• Kotlin measureNanoTime Function
• Kotlin measureTime Function

Kotlin Duration Functions

• Kotlin Duration plus Function
• Kotlin Duration minus Function
• Kotlin Duration times Function
• Kotlin Duration div Function
• Kotlin Duration toDouble Function
• Kotlin Duration toLong Function
• Kotlin Duration inWholeDays Function
• Kotlin Duration inWholeHours Function
• Kotlin Duration inWholeMinutes Function
• Kotlin Duration inWholeMilliseconds Function
• Kotlin Duration toIsoString Function
• Kotlin Duration compareTo Function
• Kotlin Duration isNegative Function
• Kotlin Duration isPositive Function

Kotlin IO Package Functions

• Kotlin byteInputStream Function
• Kotlin createTempDir Function
• Kotlin inputStream Function
• Kotlin print and println Functions
• Kotlin println Function
• Kotlin reader Function
• Kotlin readLine Function
• Kotlin readln and readlnOrNull Functions
• Kotlin readlnOrNull Function
• Kotlin use Function

Kotlin Comparisons Package Functions

• Kotlin compareBy Function
• Kotlin compareByDescending Function
• Kotlin compareValues Function
• Kotlin compareValuesBy Function
• Kotlin maxOf Function
• Kotlin minOf Function
• Kotlin naturalOrder Function
• Kotlin nullsFirst Function
• Kotlin reversed Function
• Kotlin reverseOrder Function
• Kotlin then Function
• Kotlin then Function
• Kotlin thenComparator Function

Kotlin Concurrent Package Functions

• Kotlin fixedRateTimer Function
• Kotlin thread Function

Kotlin Coroutines Package Functions

• Kotlin createCoroutine Function
• Kotlin resume Function
• Kotlin resumeWithException Function
• Kotlin startCoroutine Function