Kotlin List filterIsInstance()
Syntax & Examples

Syntax of List.filterIsInstance()

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

fun <R> Iterable<*>.filterIsInstance(): List<R>

This extension function returns a list containing all elements that are instances of specified type parameter R.

fun <R> Iterable<*>.filterIsInstance( klass: Class<R> ): List<R>

This extension function returns a list containing all elements that are instances of specified class.

✐ Examples

1 Example

In this example,

We create a list named list1 containing elements of different types.
We use the filterIsInstance function on list1 to filter only elements of type String.
The result, which is a list of strings, is stored in result.
Finally, we print the value of result to standard output using the println statement.

Kotlin Program

fun main(args: Array<String>) {
    val list1 = listOf(1, "hello", 3.14, true, 'c')
    val result = list1.filterIsInstance<String>()
    println(result)
}

Output

[hello]

2 Example

In this example,

We create a list named list2 containing elements of different types.
We use the filterIsInstance function on list2 to filter only elements of type Char.
The result, which is a list of characters, is stored in result.
Finally, we print the value of result to standard output using the println statement.

Kotlin Program

fun main(args: Array<String>) {
    val list2 = listOf("apple", 123, "banana", 'x', false)
    val result = list2.filterIsInstance<Char>()
    println(result)
}

Output

[x]

3 Example

In this example,

We create a list named list3 containing elements of different types.
We use the filterIsInstance function on list3 to filter only elements of type Int.
The result, which is a list of integers, is stored in result.
Finally, we print the value of result to standard output using the println statement.

Kotlin Program

fun main(args: Array<String>) {
    val list3 = listOf(1.5, true, 10, 'a', "world")
    val result = list3.filterIsInstance<Int>()
    println(result)
}

Output

[10]

Summary

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