kotlin 「is」演算子を使用する

if (変数 is 型) {
  処理
}

fun main() {

    var x:Any? = 123

    if(x is Byte){println("Byte")}
    else if(x is Int){println("Int")} // Int
    else if(x is Double){println("Double")}
    else if(x is Char){println("Char")}
    else if(x is String){println("String")}
    else if(x is Boolean){println("Boolean")  }

}