一.简介 根据官方API的定义: final def ==(arg0: Any): Boolean The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that). final def eq(arg0: AnyRef): Boolean Tests whether the argument (that) is a reference to the receiver object (…
先从一道题开始看: Eliminate consecutive duplicates of list elements. If a list contains repeated elements they should be replaced with a single copy of the element. The order of the elements should not be changed. Example: scala> compress(List('a, 'a, 'a, 'a…
欢迎关注我的新博客地址:http://cuipengfei.me/blog/2014/10/31/spark-fold-aggregate-why-not-foldleft/ 大家都知道Scala标准库的List有一个用来做聚合操作的foldLeft方法. 比方我定义一个公司类: 1 case class Company(name:String, children:Seq[Company]=Nil) 它有名字和子公司. 然后定义几个公司: 1 val companies = List(Compa…
object collection_t1 { def flatMap1(): Unit = { val li = List(,,) val res = li.flatMap(x => x match { => List('a','b') ) }) println(res) } def map1(): Unit = { val li = List(,,) val res = li.map(x => x match { => List('a','b') }) println(res)…