How to correctly concatenate strings in Kotlin?

There are different ways to concatenate strings in Kotlin. For example, we can use the $ operator or we can use the append() function or we can simply use the "+" operator to join two strings.

Example – Concatenate Using "$"

Kotlin provides an operator to reference a variable or expression. In this example, we will see how to concatenate two strings using the "$" operator.

fun main(args: Array<String>) {
   val a = "Tutorialspoint"
   val b = ".com"
   println("String 1: " + a)
   println("String 2: " + b)
   println("Concatenated String: " + "$a$b")
}

Output

It will produce the following output −

String 1: Tutorialspoint
String 2: .com
Concatenated String: Tutorialspoint.com

Example – Concatenate Using append()

In this example, we will see how we can use String Builder object’s append() to concatenate two different strings into one. We will modify the above example in order to implement the same.

fun main(args: Array<String>) {
   val a = "Tutorialspoint"
   val b = ".com"
   println("String 1: " + a)
   println("String 2: " + b)
   println("Concatenated String: " + StringBuilder().append(a).append(b).toString())
}

Output

It will produce the following output −

String 1: Tutorialspoint
String 2: .com
Concatenated String: Tutorialspoint.com

Example – Concatenate Using "+"

We can simply use the "+" operator to concatenate strings. Let's modify the above example.

fun main(args: Array<String>) {
   val a = "Tutorialspoint"
   val b = ".com"
   println("String 1: " + a)
   println("String 2: " + b)
   println("Concatenated String: " + a+b)
}

Output

It will produce the following output −

String 1: Tutorialspoint
String 2: .com
Concatenated String: Tutorialspoint.com