Kotlin List filterIsInstanceTo()
Syntax & Examples

Syntax of List.filterIsInstanceTo()

There are 2 variations for the syntax of List.filterIsInstanceTo() extension function. They are:

fun <R, C : MutableCollection<in R>> Iterable<*>.filterIsInstanceTo( destination: C ): C

This extension function appends all elements that are instances of specified type parameter R to the given destination.

fun <C : MutableCollection<in R>, R> Iterable<*>.filterIsInstanceTo( destination: C, klass: Class<R> ): C

This extension function appends all elements that are instances of specified class to the given destination.

✐ Examples

1 Example

In this example,

We create a list named list containing elements of different types: integers, strings, characters, and a double.
We create an empty mutable list named result to store filtered integers.
We apply the filterIsInstanceTo extension function on list to filter out only the integers and append them to result.
Finally, we print the result list to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf(1, "two", 3.0, '4', 5);
    val result = mutableListOf<Int>();
    list.filterIsInstanceTo(result);
    println(result);
}

Output

[1, 5]

2 Example

In this example,

We create a list named list containing elements of different types: characters, integers, and strings.
We create an empty mutable list named result to store filtered characters.
We apply the filterIsInstanceTo extension function on list to filter out only the characters and append them to result.
Finally, we print the result list to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf('a', 1, 'b', "two", 'c');
    val result = mutableListOf<Char>();
    list.filterIsInstanceTo(result);
    println(result);
}

Output

[a, b, c]

3 Example

In this example,

We create a list named list containing elements of different types: strings and integers.
We create an empty mutable list named result to store filtered strings.
We apply the filterIsInstanceTo extension function on list to filter out only the strings and append them to result.
Finally, we print the result list to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf("apple", 10, "banana", 20, "orange", 30);
    val result = mutableListOf<String>();
    list.filterIsInstanceTo(result);
    println(result);
}

Output

[apple, banana, orange]

Summary

In this Kotlin tutorial, we learned about filterIsInstanceTo() extension function of List: the syntax and few working examples with output and detailed explanation for each example.