scala> //定义一个方法scala> def m(x:Int) = 2*xm: (x: Int)Intscala> //定义一个函数scala> val f = (x:Int) => 2*xf: Int => Int = <function1>scala> //方法不能作为最终表达式出现scala> m<console>:9: error: missing arguments for method m;follow this method with `_‘ if you want to treat it as a partially applied function