第87讲：Scala中使用For表达式做查询

第87讲：Scala中使用For表达式做查询

case class Book(title : String , authors : List[String]) object For_Query {

  def main(args: Array[String]) {     val books: List[Book] = List(     Book("Structure and Interpretation ", List("Abelson , Harold", "Sussman")),     Book("Principles of Compiler Design",       List("Aho, Alfred", "Ullman, Jeffrey")),     Book("Programming in Modula-2", List("Wirth, Niklaus")),     Book("Introduction to Functional Programming", List("Bird, Richard")),     Book("The Java Language Specification",       List("Gosling, James", "Joy, Bill", "Steele, Guy", "Bracha, Gilad")))     //    val result = for(b