kotlin
fun String.calculateLength(): Int {
return this.length
}
kotlin
val length = "Hello World".calculateLength()
kotlin
val nullableString: String? = null
if (nullableString != null) {
val length = nullableString.length
}
kotlin
val length = nullableString?.length ?: 0
kotlin
data class User(val id: Int, val name: String)
kotlin
val user = User(1, "Alice")
val userId = user.id
val userName = user.name
kotlin
val numbers = listOf(1, 2, 3, 4, 5, 6)
val evenNumbers = numbers.filter { it % 2 == 0 }
