Kotlin Strings

A String is a value that holds text. A String can be measured, read one character at a time, and joined with other strings.

The length of a name

The word length after a dot gives the character count of the string. The name Maya has four characters.

fun main() {
    val name = "Maya"
    println(name.length)
}

Characters by position

Square brackets read the character at one position. Position 0 gives the first letter and position 5 gives the last letter of this word.

fun main() {
    val word = "kotlin"
    println(word[0])
    println(word[5])
}

Joining strings with +

The + sign joins two strings end to end. The joined text prints as one line with nothing added between the parts.

fun main() {
    val first = "Hello, "
    val second = "Ana"
    println(first + second)
    println("sun" + "shine")
}

The last character

The last position of a string is its length minus one. Reading that position gives the final letter.

fun main() {
    val word = "garden"
    println(word[word.length - 1])
}

Example

fun main() {
    val city = "Paris"
    println(city.length)
    println(city[0])
    val greeting = "Welcome to " + city
    println(greeting)
}

Key points

length: the number of characters in a string.
Use square brackets with a position to read one character from a string.
The first character of a string sits at position 0.
Use + to join two strings into one longer string.

In this example, city holds the text Paris. The length print shows 5 characters. The position print shows P, the character at position 0. The last print joins the greeting text with city and shows Welcome to Paris.

Note

A space inside a string counts as a character in its length.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Kotlin Playground

fun main() {
    val city = "Paris"
    println(city.length)
    println(city[0])
    val greeting = "Welcome to " + city
    println(greeting)
}

Exercise

What does println("code"[2]) print?

c o e d