scala>defsayHelloWorld:Unit=println("hello, world")defsayHelloWorld:Unitscala>sayHelloWorldhello,worldscala>sayHelloWorld()^error:Unitdoesnottakeparameters 3)return缺省。绝大多数情况下可以省略return,此时方法体中的最后一句代码执行结果即为该方法的返回值,一般仅需在提前终止代码块执行并返回结果时才需使用,...
有人能解释一下以下代码的细微差别吗?(使用scala 2.10.2) 案例1 scala> def greet = println("helloo") greet: Unit scala> greet helloo scala> greet() <console>:9: error: Unit does not take parameters greet() ^ 案例2 scala> def greet = 浏览1提问于2013-08-02得票数 2 6回答 Scala ` ...
scala>valarr=newArrayBuffer[Int]<console>:11:error:notfound:typeArrayBuffervalarr=newArrayBuffer[Int]^// 变长数组需要手动引入scala>importscala.collection.mutable.ArrayBufferimportscala.collection.mutable.ArrayBufferscala>valarr=newArrayBuffer[Int]arr:scala.collection.mutable.ArrayBuffer[Int]=ArrayBuffer()//...
scala>object FooMarker2{|defapply2()=newFoo|}defined object FooMarker2 scala>val newFoo2=FooMarker2()<console>:13:error:FooMarker2.type does not take parameters val newFoo2=FooMarker2()^ 在类中,创建 val bar = new Bar 之后,调用 bar() 便会触发该类的apply()。同样,class中没有定义app...
(1)<console>:13:error:Anydoes not take parametersarr(2)(1)^// Any类型什么也干不了,需要强转成指定类型scala>res37.asInstanceOf[Array[Int]]res39:Array[Int]=Array(1,2,3)scala>res39(1)res40:Int=2scala>val arr=Array[Int](1,4,2,5,6,7)arr:Array[Int]=Array(1,4,2,5,6,7)//...
@SethTisue: "In Scala through 2.12, .iterator has no parameter lists and the compiler says 'Iterator[...] does not take parameters' if you write .iterator(). So somebody made a different decision on this years ago. Just leaving it like it was doesn't feel terrible to me. Even if yo...
Why Scala does NOT have “static” keyword? What is the main reason for this decision? As we know, Scala does NOT have “static” keyword at all. This is the design decision done by Scala Team. The main reason to take this decision is to make Scala as a Pure Object-Oriented Language...
(1, 3, 4, 5, 6, 8, 9, 2) scala> for(i <- arr) | print(i) 13456892 scala> for(i <- (arr.length to 0)) | print(arr[i]) <console>:20: error: not found: type i print(arr[i]) ^ <console>:20: error: value arr of type Array[Int] does not take type parameters. ...
Finally, we didn’t really need to compile the file, because the SBT build does that for us. We could run it at the SBT prompt using this command: > run-main progscala2.introscala.Upper Hello World! Using the scala command, we need to point to the correct directory where SBT writes...
Call-by-name means evaluates method/function parameters only when we need them or we access them. If we don’t use them, then it does not evaluate them. Scala supports both call-by-value and call-by-name function parameters. However, Java supports only call-by-value, but not call-by-...