Scala 数据类型详解

val a: Byte = 100
val b: Short = 20000
val c: Int = 1000000
val d: Long = 10000000000L

val e: Float = 3.14F
val f: Double = 3.1415926535

val g: Boolean = true
val h: Boolean = false

val i: Char = 'A'
val j: Char = '\u0041' // Unicode 表示

def printMessage(): Unit = println("Hello, Scala!")
val result: Unit = printMessage() // 输出 "Hello, Scala!"，返回 ()

val k: String = "Hello, Scala!"
val l: String = """多行
字符串"""

val m: List[Int] = List(1, 2, 3)
val n: Set[String] = Set("A", "B", "C")
val o: Map[Int, String] = Map(1 -> "One", 2 -> "Two")

class Person(val name: String, val age: Int)
val p: Person = new Person("Alice", 25)

val q = 42 // 推断为 Int
val r = 3.14 // 推断为 Double
val s = "Scala" // 推断为 String

val t: Int = 100
val u: Double = t.toDouble
val v: String = t.toString

val w: Any = "Hello"
if (w.isInstanceOf[String]) {
  val x: String = w.asInstanceOf[String]
  println(x.toUpperCase) // 输出 "HELLO"
}

val y: Option[String] = Some("Scala")
val z: Option[String] = None
y match {
  case Some(value) => println(value)
  case None => println("No value")
}

val result: Either[String, Int] = Right(42)
result match {
  case Left(error) => println(s"Error: $error")
  case Right(value) => println(s"Value: $value")
}