CODEWITHSUNDEEP
scala
CoolGoose
CoolGoose

Reputation: 160

extract map from nested case classes

I have a json value which i have read into nested case class. From this i need a scala map of (category,rating).Please help.

Expected output:

Map("MTH1"-> "9A","MTH2"-> "9B","SCI1" -> "8A")

Note: If any value is none, then it should be omitted.

Need some elegant and smart way to convert the values into scala Map

 val myVal: List[myClass] = List(myClass("Tim", "100", Some("hills"),
    List(subject("geometry", Some("MTH1"), Some("9A")),
      subject("trigonometry", Some("MTH2"), Some("9B")),
      subject("physics", Some("SCI1"), Some("8A"))
    )))


  case class myClass(
                      name: String,
                      classId: String,
                      teacher: Option[String],
                      subjects: List[subject]
                    )


  case class subject(
                      name: String,
                      category: Option[String],
                      rating: Option[String]
                    )

  myVal.foreach(i =>
    (
      i.subjects.foreach(
        j => println(j.category.get, j.rating.get)
      )))

Upvotes: 1

Views: 237

Answers (1)

jwvh
jwvh

Reputation: 51271

The will return a List[Map[String,String]]:

myVal.map(_.subjects
           .collect{
             case subject(_,Some(cat),Some(rat)) => cat -> rat
           }.toMap)

Each element of the original List is turned into a Map of category -> rating (key -> value) pairs.

Upvotes: 4

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