By definition, it looks like this− inline fun List(Īs we pass an initial default value, it creates a read only list of specified number of elements. In order to create a mutable list of repeating elements, we will be using Kotlin List(). Example – Creating a Mutable List in Kotlin The Mutable List inherits form the Generic class. A mutable list grows automatically in size as we insert new elements into it. Once a collection is declared as mutable, it becomes dynamic and we can modify its data as per requirement. This effectively means that if we pass in T we get out an array Array.A Mutable List is an interface and generic collection of elements. If we dig deep into Kotlin Standard Library, the function arrayOf() is actually returning Array where T is the type of the elements in the array. Now, let’s look at 2D array initialization and usage examples in kotlin! 2D Arrays in KotlinĢD arrays are a convenient way to store grid/board/matrix type of data. Mutable lists provide a lot more functions: get(), set(), plus, minus(), etc. indices ) // You can also use listOrArray to access the element at the given index. The below code works for both lists and arrays for ( i in listOrArray. Here are examples to declare a type-safe mutable lists with various examples: MutableListOf() allows us to manually define type-safe lists. If you pass in multiple data types in the constructor, the list will automatically be of type Any. To explicitly allow for it, use mutableListOf() to add mixed data types to the list. Note: Unlike arrayOf(), once mutableListOf() automatically infers a single data type, you can’t change the data type of the list.

Using them, we can add, remove, or modify the elements in the list without re-creating it! It works similar to arrayOf(), but provides us functions to perform actions on the list. 1D arrays with dynamic sizeįor lists of dynamic size, we use the function mutableListOf(). Kotlin standard library supports for functions like intArrayOf(), doubleArrayOf(), booleanArrayOf(), etc.

It is pretty useful if you want to store data that is strongly typed. Type mismatch: inferred type is String but Int was expected

Empty mutable list kotlin