toByteArray

Encodes the contents of this string using the specified character set and returns the resulting byte array.

inline fun String.toByteArray(charset: Charset = Charsets.UTF_8): ByteArray(source)

fun main() {
    val text = "Hello, Kotlin!"
    val bytes = text.toByteArray(Charsets.UTF_8)
    println(bytes.joinToString(prefix = "[", postfix = "]") { it.toString() })
}

Source