learning scala stream collection

【learning scala stream collection】的更多相关文章

learning scala stream collection

最关键的部分是计算序列的同时,不会引发无限递归, #:: 表达式的右边只有在被请求时才会被求值.…

learning scala view collection

The view method will create a non-strict version of the collection which means that the elements of the collection will only be made available at access time. val lazyLargeOddNumberList = ( to ).view.filter(_ % != ).take().toList…

learning scala control statement

1 .if satement 与其它语言不同的是,scala if statement 返回的是一个值 scala> val a = if ( 6 > 0 ) 1 else -1a: Int = 1 2. while statement 3. do.. while statement 4 for statement for ( 变量 <- 表达式 ) { 语句块}: scala> for ( i <- 1 to 3 ) println(i)123 scala> for…

learning scala How To Create Variable Argument Function - varargs :_ *

Scala collection such as List or Sequence or even an Array to variable argument function using the syntax :_ *. code : def printReport(names: String*) { println(s"""Donut Report = ${names.mkString(" - ")}""") } prin…

learning scala 数组和容器

数组:可变的,可索引的,元素具有相同类型的数据集合一维数组 scala> val intValueArr = new Array[Int](3)intValueArr: Array[Int] = Array(0, 0, 0) scala> val myStrArr = Array("BigData","hadoop","spark")myStrArr: Array[String] = Array(BigData, hadoop, s…

learning scala read from file

scala读文件: example: scala> import scala.io.Sourceimport scala.io.Source scala> var inputFile = Source.fromFile("text.txt")inputFile: scala.io.BufferedSource = non-empty iterator scala> for ( line <- inputFile.getLines()) println(lin…

learning scala write to file

scala 写文件功能: scala> import java.io.PrintWriterimport java.io.PrintWriter scala> val outputFile = new PrintWriter("text.txt")outputFile: java.io.PrintWriter = java.io.PrintWriter@213c812a scala> outputFile.println("hello panzidong&q…

learning scala output to console

控制台输出语句: print println example: scala> print("i=");print(i)i=345scala> println("hello ");println("world")hello world…

learning scala read from console

控制台输入语句: readInt, readDouble, readByte, readShort, readLong, readChar, readBoolean, readLine example:scala> import io.StdIn._import io.StdIn._ scala> var i=readInt()2i: Int = 2 scala> var f=readFloat()2.2f: Float = 2.2 scala> var b=readBoolean…

learning scala 变量

scala 变量: val : 声明时,必须被初始化,不能再重新赋值. scala> test = "only1"<console>:11: error: not found: value test test = "only1" ^<console>:12: error: not found: value test val $ires0 = test ^ var :可被多次赋值. scala> var test2 = &qu…

learning scala 操作符

scala 操作符: 算术运算符: + - * / % 关系统运算符: > , < ,= ,!= ,>=,<=, 逻辑运算符: && . || , ! 位运算符:&, |, ^,~,<<,>>,>>>(无符号右移) 赋值运算符: = 优先及由上及下…

learning scala akka ask_pattern

package com.example import akka.actor._ import akka.util.Timeout object Tutorial_03_Ask_Pattern extends App { val system = ActorSystem("DonutStoreActorySystem") val donutInfoActor = system.actorOf(Props[DonutInfoActor], name="DonutInfoActor…

learning scala akka actorySystem create and close

package com.example import akka.actor.ActorSystem import scala.util.{Failure, Success} import scala.concurrent.ExecutionContext.Implicits.global object Tutorial_01_ActorSystem_Introduction extends App { println("Step1 : Create an actor system")…

learning scala list.collect

collect will apply a partial function to all elements of a Traversable and return a different collection…

learning scala someElements

The Scala collections library provides specialised implementations for Sets of fewer than 5 values (see the source). The iterators for these implementations return elements in the order in which they were added, rather than the consistent, hash-based…

learning scala PartialFunction

Partial函数的定义 scala> val isVeryTasty: PartialFunction[String, String] = { case "Glazed Donut" | "Strawberry Donut" => "Very Tasty"}isVeryTasty: PartialFunction[String,String] = <function1> scala> isVeryTasty(&qu…

learning scala Function Recursive Tail Call

可以使用scala库,可以从字面上看出是在调用递归函数: code import scala.util.control.TailCalls._ val arrayDonuts: Array[String] = Array("Vanilla Donut", "Strawberry Donut", "Plain Donut", "Glazed Donut") println("\nStep : How to defin…

learning scala generic classes

package com.aura.scala.day01 object genericClasses { def main(args: Array[String]): Unit = { val stack = new Stack[Int] stack.push() stack.push() println(stack.pop()) println(stack.pop()) } } class Stack[A] { private var elements: List[A] = Nil def p…