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 = 5 scala> var a = 123 a: Int = 123 scala> a = 124 a: Int = 124 scala> val b = "demo" b: String = demo scala> b = "demo2" <console>:27: error: reassignment to val          b = "demo2"            ^

函数

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

匿名函数

scala> (x:Int)=>x+1 res0: Int => Int = <function1> scala> var addOne = (x:Int)=>x+1 addOne: Int => Int = <function1> 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) => Int scala> 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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