Kotlin Array - contains() Function

The Kotlin array contains() function checks if the specified element is present in the array. It returns true if the element is found; otherwise, it returns false.

This function is useful for searching for a specific value in the array.

Syntax

Following is the syntax of Kotlin array contains() function −

operator fun <T> Array<out T>.contains(element: T): Boolean

Parameters

This function accepts an element as a parameter that represents an element of an array to be searched.

Return value

This function returns a boolean value: true if the array contains the element, and false otherwise.

Example 1

Following is the basic example, we create an array displaying the elements. We then use contains() function to check specified element is present or not −

fun main(args: Array<String>) {
   var array = Array(10) { i -> i}
   var result = array.count()
   println("The elements in the array is(are): ")
   for (i in 0..result-1) {
      println("array[$i] = ${array[i]}")
   }
   val check = 100
   if(array.contains(check)) {
      println("The array contains the element $check")
   } else {
      println("The array doesn't contain the element $check")
   }
}

Output

Following is the output −

The elements in the array is(are): 
array[0] = 0
array[1] = 1
array[2] = 2
array[3] = 3
array[4] = 4
array[5] = 5
array[6] = 6
array[7] = 7
array[8] = 8
array[9] = 9
The array doesn't contain the element 100

Example 2

Now, let's see another example. Here, we create an array. We then use contains() to check whether specified element is present −

fun main(args: Array<String>) {
   var array = Array(5) { i -> i}
   var result = array.count()
   val check = 4
   if(array.contains(check)) {
      println("The array contains $check")
   } else {
      println("The array doesn't contain the element $check")
   }
}

Output

Following is the output −

The array contains 4

Example 3

The example below creates an array with random values. Then, we use the contains() to check the specified element is available or not −

fun main(args: Array<String>) {
   var array = arrayOf(10, 23.4, "kotlin", "tutorialspoint")
   var result = array.count()
   println("The elements in the array are: ")
   for (i in 0..result-1) {
      println("array[$i] = ${array[i]}")
   }
   val check = "tutorix"
   if(array.contains(check)) {
      println("The array contains the element $check")
   } else {
      println("The array doesn't contain the element $check")
   }
}

Output

Following is the output −

The elements in the array are: 
array[0] = 10
array[1] = 23.4
array[2] = kotlin
array[3] = tutorialspoint
The array doesn't contain the element tutorix