How to insert character at specific index in string in Kotlin?

In this tutorial, you shall learn how to insert a character at specific index in a given string in Kotlin, using String.substring() function, with the help of examples.

Kotlin – Insert character at specific index in string

To insert a character at specific index in string in Kotlin, you can use String.substring() function.

Find the substring from starting to the specified index in the string. Then find the substring from the index to the end of the string. Now, concatenate the first part, the character, and the second part into a single string.

Syntax

The syntax to insert character ch at index index in string str is

str.substring(0, index) + ch + str.substring(index)

Examples

1. Insert character ‘m’ at index=4 in string

In the following program, we take a string in str, and insert the character 'm' at index=3.

Main.kt

fun main() {
    var str = "hello world"
    val ch = 'm'
    val index = 3
    str = str.substring(0, index) + ch + str.substring(index)
    println(str)
}

Output

helmlo world

Related Tutorials

• Kotlin – Find substring of a string

Conclusion

In this Kotlin Tutorial, we learned how to insert a character at specific index in string using String.substring() function.