高阶函数 filter 源码分析
package com.dt.scala.forexpression
case class Person(name: String, isMale: Boolean, children: Person*)
object For_Expressive {
def main(args: Array[String]) {
val lauren = Person("Lauren", false)
val rocky = Person("Rocky", true)
val vivian = Person("Vivian", false, lauren, rocky)
val persons = List(lauren, rocky, vivian)
val result = persons filter (person => !person.isMale) flatMap(person =>
(person.children map (child => (person.name, child.name))))
println(result)
val forResult = for (person <- persons; if !person.isMale; child <- person.children)
yield (person.name, child.name)
println(forResult)
}
}
flatMap, 压扁，是将2个集合合并。
用for循环一样能实现示例中的功能，表达力更清晰。
for循环背后是flatMap的方式，跳转代码能直接看到flatMap。强大的功能。
