spark的匿名函数怎么使用

本篇内容主要讲解"spark的匿名函数怎么使用"，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习"spark的匿名函数怎么使用"吧!

变量与常量

scala> var a = addOne(4)a: Int = 5scala> var a = 123a: Int = 123scala> a = 124a: Int = 124scala> val b = "demo"b: String = demoscala> b = "demo2":27: error: reassignment to val         b = "demo2"           ^

函数

scala> def addOne(m:Int):Int = {     | m+1     | }addOne: (m: Int)Intscala> var a = addOne(4)a: Int = 5

匿名函数

scala> (x:Int)=>x+1res0: Int => Int = scala> var addOne = (x:Int)=>x+1addOne: Int => Int = scala> addOne(3)res1: Int = 4

多行匿名函数，传入多个参数

scala> def mult = {(x:Int,y:Int)=>     | var z = x * y     | z+19     | }mult: (Int, Int) => Intscala> mult(4,5)res6: Int = 39

对象

scala> class Person{                                                                                                     | var age : Int = 30                                                                                                | def grow() : Int = {                                                                                              | age =age +1                                                                                                       | age                                                                                                               | }                                                                                                                 | }                                                                                                            defined class Person                                                                                                                                                                                                                    scala> var person = new Person                                                                                      person: Person = $iwC$$iwC$Person@2183cb14                                                                                                                                                                                              scala> person.grow()                                                                                                res2: Int = 31                                                                                                                                                                                                                          scala> person.grow()                                                                                                res3: Int = 32

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