let
`fun main(args:Array<String>){
val person = Person()
println(person.toString())
person.let {
it.name = "Peter"
it.age = 20
}
println(person.toString())
}
data class Person(var name: String ="", var age:Int = 0)`
with
val p1 = with(Person()) { name = "zhangsan" age = 20 return@with this }
apply
val p2 = Person().apply { name = "lisi" age = 25 }
