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

How It Works

This Kotlin program demonstrates Is Operator (is and !is). It first prepares the data it needs, then uses conditional logic to decide the result, and finally prints the output shown in the Sample Output above.

1. Declare the variables that hold the program’s data.
2. Use conditional statements to handle the different cases.
3. Print the final result to the console so you can compare it with the sample output.

Try changing the input values and re-running the program to see how the output changes — this is the fastest way to understand how the logic behaves.