Is Operator (is and !is) in Kotlin


Definition

  • Is operators are used to check if a variable is of a particular type or not(!is) in Kotlin.
  • This operator is mainly used in when and if statements.
  • This operator is equivalent to the "instanceOf" method in Java.

Syntax

1. is Operator

if(value is variable_type){
	//Block of Code
}

For example,

if(value is String){
	println("$value is a String")
}

2. !is Operator

if(value !is variable_type){
	//Block of Code
}

For example,

if(value !is String){
	println("$value is not a String")
}

Is and !is Operator Example Program in Kotlin

//Is Operator Example Program in Kotlin
//Operator Kotlin Programs, Basic Kotlin Program
fun main(args: Array<String>) {
    val name = "Little Drops"
    val number = 5

    println("Checking data type of : $name")
    checkDataType(name)
    println()
    println("Checking data type of : $number")
    checkDataType(number)
}

fun checkDataType(value : Any){
    if(value is String){
        println("$value is a String")
    }

    if(value !is String){
        println("$value is not a String")
    }

    if(value is Int){
        println("$value is an Int")
    }

    if(value !is Int){
        println("$value is not an Int")
    }
}

Sample Output

Checking data type of : Little Drops
Little Drops is a String
Little Drops is not an Int

Checking data type of : 5
5 is not a String
5 is an Int