Created
January 4, 2018 16:55
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How to convert flat data to structured case classes
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case class B(name: String) | |
case class A(name: String, seq: Seq[B]) | |
case class X(name: String, seq: Seq[A]) | |
val data: Seq[Tuple3[String, String, String]] = Seq( | |
("X", "Left", "Some value"), | |
("X", "Left", "Some other value"), | |
("X", "Right", "A third value"), | |
("X", "Right", "Fourth value") | |
) | |
val structuredData = X("X", Seq( | |
A("A", Seq( | |
B("Some value"), | |
B("Some other value") | |
)), | |
A("B", Seq( | |
B("A third value"), | |
B("Fourth value") | |
)) | |
)) | |
println(structuredData) | |
val structuredByUglyCode = data | |
.groupBy(_._1) // group by "X" | |
.mapValues(_.groupBy(_._2)) // group by "Left" and "Right" | |
.mapValues(_.mapValues(_.map(t => B(t._3)))) // Remove the grouped values from inner-most tuple and map to B | |
.mapValues(_.map { case (k, v) => A(k, v) }) // middle layer from `"Left" -> List(B("Some value"), B("Some other value"))` to `A(....) | |
.map { case (k, v) => X(k, v.toSeq) } // Map outer-most layer to List(X(...)) |
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