Onnowpurbo at 03:02, 23 July 2022

2022-07-23T03:02:11Z

Onnowpurbo: Created page with "Sumber: https://www.tutorialspoint.com/kotlin/kotlin_collections.htm Collections are a common concept for most programming languages. A collection usually contains a number..."

2022-07-18T02:36:20Z

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Sumber: https://www.tutorialspoint.com/kotlin/kotlin_collections.htm

Collections are a common concept for most programming languages. A collection usually contains a number of objects of the same type and Objects in a collection are called elements or items.

The Kotlin Standard Library provides a comprehensive set of tools for managing collections. The following collection types are relevant for Kotlin:

Kotlin List - List is an ordered collection with access to elements by indices. Elements can occur more than once in a list.

Kotlin Set - Set is a collection of unique elements which means a group of objects without repetitions.

Kotlin Map - Map (or dictionary) is a set of key-value pairs. Keys are unique, and each of them maps to exactly one value.

Kotlin Collection Types
Kotlin provides the following types of collection:

Collection or Immutable Collection

Mutable Collection

Kotlin Immutable Collection
Immutable Collection or simply calling a Collection interface provides read-only methods which means once a collection is created, we can not change it because there is no method available to change the object created.

Collection Types Methods of Immutable Collection
List listOf()
listOf<T>()
Map mapOf()
Set setOf()
Example
fun main() {
val numbers = listOf("one", "two", "three", "four")

println(numbers)
}
When you run the above Kotlin program, it will generate the following output:

[one, two, three, four]
Kotlin Mutable Collection
Mutable collections provides both read and write methods.

Collection Types Methods of Immutable Collection
List ArrayList<T>()
arrayListOf()
mutableListOf()
Map HashMap
hashMapOf()
mutableMapOf()
Set hashSetOf()
mutableSetOf()
Example
fun main() {
val numbers = mutableListOf("one", "two", "three", "four")

numbers.add("five")

println(numbers)
}
When you run the above Kotlin program, it will generate the following output:

[one, two, three, four, five]
Note that altering a mutable collection doesn't require it to be a var.
Quiz Time (Interview & Exams Preparation)
Q 1 - Which of the following is true about Kotlin Collections?

A - Kotlin provides mutable and immutable collection

B - List, Set and Map are Kotlin Collections

C - Kotlin Map can store values in Key-Value pairs

D - All of the above

Q 2 - What will be the output of the following program:

fun main() {
val numbers = listOf("one", "two", "three", "four")

numbers = listOf("five")
}
A - This will print 0

B - This will raise just a warning

C - Compilation will stop with error

D - None of the above

Q 2 - Which statement is not correct?

A - Kotlin List can have duplicate values

B - Kotlin Set can not have duplicate values

C - Immutable collection does not provide methods to change/update the collection.

D - Kotlin does not provide collection types: sets, lists, and maps

==Referensi==

* https://www.tutorialspoint.com/kotlin/kotlin_collections.htm

@@ Line 7: / Line 7: @@
 The Kotlin Standard Library provides a comprehensive set of tools for managing collections. The following collection types are relevant for Kotlin:
-Kotlin List - List is an ordered collection with access to elements by indices. Elements can occur more than once in a list.
+ Kotlin List - List is an ordered collection with access to elements by indices. Elements can occur more than once in a list.
-Kotlin Set - Set is a collection of unique elements which means a group of objects without repetitions.
+==Kotlin Collection Types==
 Kotlin provides the following types of collection:
-Collection or Immutable Collection
+ Collection or Immutable Collection
-Mutable Collection
+==Kotlin Immutable Collection==
 Immutable Collection or simply calling a Collection interface provides read-only methods which means once a collection is created, we can not change it because there is no method available to change the object created.
-Collection Types	Methods of Immutable Collection
+ Collection Types	Methods of Immutable Collection
-List	listOf()
+ List	listOf()
-listOf<T>()
+ listOf<T>()
-Map	mapOf()
+ Map	mapOf()
-Set	setOf()
+ Set	setOf()
 Example
-fun main() {
+==Example==
-    val numbers = listOf("one", "two", "three", "four")
+ fun main() {
-    println(numbers)
+     val numbers = listOf("one", "two", "three", "four")
-−
 When you run the above Kotlin program, it will generate the following output:
-[one, two, three, four]
+ [one, two, three, four]
 Kotlin Mutable Collection
 Mutable collections provides both read and write methods.
-Collection Types	Methods of Immutable Collection
+ Collection Types	Methods of Immutable Collection
-List	ArrayList<T>()
+ List	ArrayList<T>()
-arrayListOf()
+ arrayListOf()
-mutableListOf()
+ mutableListOf()
-Map	HashMap
+ Map	HashMap
-hashMapOf()
+ hashMapOf()
-mutableMapOf()
+ mutableMapOf()
-Set	hashSetOf()
+ Set	hashSetOf()
-mutableSetOf()
+ mutableSetOf()
 Example
-fun main() {
+===Example===
-    val numbers = mutableListOf("one", "two", "three", "four")
+ fun main() {
-    numbers.add("five")
+     val numbers = mutableListOf("one", "two", "three", "four")
-−
-    println(numbers)
+     numbers.add("five")
-−
 When you run the above Kotlin program, it will generate the following output:
-[one, two, three, four, five]
+ [one, two, three, four, five]
 Note that altering a mutable collection doesn't require it to be a var.
 Quiz Time (Interview & Exams Preparation)
 Q 1 - Which of the following is true about Kotlin Collections?

KOTLIN: Collection - Revision history

Onnowpurbo at 03:02, 23 July 2022

Onnowpurbo: Created page with "Sumber: https://www.tutorialspoint.com/kotlin/kotlin_collections.htm Collections are a common concept for most programming languages. A collection usually contains a number..."