capitalize

Common
JVM
JS
Native
1.0
fun String.capitalize(): String

Returns a copy of this string having its first letter titlecased using the rules of the default locale, or the original string if it's empty or already starts with a title case letter.

The title case of a character is usually the same as its upper case with several exceptions. The particular list of characters with the special title case form depends on the underlying platform.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
println("abcd".capitalize()) // Abcd
println("Abcd".capitalize()) // Abcd
//sampleEnd
}
JVM
1.4
fun String.capitalize(locale: Locale): String

Returns a copy of this string having its first letter titlecased using the rules of the specified locale, or the original string if it's empty or already starts with a title case letter.

The title case of a character is usually the same as its upper case with several exceptions. The particular list of characters with the special title case form depends on the underlying platform.