scala =>符号的使用

一、

// => 匿名函数， 左边是参数 右边是函数实现体
val list = List(1, 2, 3).map { (x: Int) => x * 2 }
println(list)
二、

// => 函数类型的声明,左边是参数类型，右边是方法返回值类型
val g:(Int) => String = myInt => {"my int: "+myInt.toString}
val h: () => Unit = () => { println("x")}
三、

// => 指定参数为call-by-name;By-name-parameter
def and(x: Boolean, y: => Boolean) =
if (x) y else false
四、

// => case 语句中 case x => y 匹配到x则返回y
val firstArg = "salt1"
val friend =
firstArg match {
case "salt" => "pepper"
case "chips" => "salsa"
case "eggs" => "bacon"
case _ => "huh?"
}
println(friend)