基本数据类型

Byte/Char
Short/Inr/Long/Double/Float
Boolean

  1. scala> val a :Int = 1
  2. a: Int = 1
  3. scala> val b :Boolean = true
  4. b: Boolean = true

浮点型

  1. scala> val c :Float = 1.234f
  2. c: Float = 1.234

类型转换

  1. scala> val d = 1.asInstanceOf[Double]
  2. d: Double = 1.0

判断数据类型

  1. scala> val f = 2.isInstanceOf[Int]
  2. f: Boolean = true
  3. scala> val g = 2.1234.isInstanceOf[Double]
  4. g: Boolean = true
  5. scala> val e = 2.1234f.isInstanceOf[Float]
  6. e: Boolean = true

lazy
如果变量或者常量声明成lazy ,第一次使用才会计算与赋值

  1. scala> lazy val h = 1
  2. h: Int = <lazy>
  4. scala> h
  5. res0: Int = 1

字符串

字符串拼接 不能省略s,应用字符串插值需要使用$符号

  1. val h = "Hadoop"
  2.     val s = s"hello $h"
  3.     println(s)

字符串多行显示

  1. val b =
  2.       """
  3.         |hello world
  4.         |hello spark
  5.       """.stripMargin
  6.     println(b)