Kotlin List find()
Syntax & Examples

Syntax of List.find()

The syntax of List.find() extension function is:

fun <T> Iterable<T>.find(predicate: (T) -> Boolean): T?

This find() extension function of List returns the first element matching the given predicate, or null if no such element was found.


✐ Examples

1 Example

In this example,

  • We create a list named list1 containing integers.
  • We use the find function on list1 with a predicate that finds the first even number.
  • The result, which is the first even number in the list, 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, 2, 3, 4, 5)
    val result = list1.find { it % 2 == 0 }
    println(result)
}

Output

2

2 Example

In this example,

  • We create a list named list2 containing strings.
  • We use the find function on list2 with a predicate that finds the first string with length greater than 5.
  • The result, which is the first string with length greater than 5 in the list, 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", "banana", "cherry")
    val result = list2.find { it.length > 5 }
    println(result)
}

Output

banana

3 Example

In this example,

  • We create a list named list3 containing characters.
  • We use the find function on list3 with a predicate that finds the first lowercase character.
  • The result, which is the first lowercase character in the list, 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('a', 'b', 'c', 'd', 'e')
    val result = list3.find { it.isLowerCase() }
    println(result)
}

Output

a

Summary

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