Question

After reading a JSON result from a web service response:

val jsonResult: JsValue = Json.parse(response.body)

Containing content something like:

{
    result:  [
    ["Name 1", "Row1 Val1", "Row1 Val2"],
    ["Name 2", "Row2 Val1", "Row2 Val2"]
             ]
 }

How can I efficiently map the contents of the result array in the JSON with a list (or something similar) like:

val keys = List("Name", "Val1", "Val2")

To get an array of hashmaps?

Answer 1

Something like this ?
This solution is functional and handles None/Failure cases “properly” (by returning a None)

val j = JSON.parseFull( json ).asInstanceOf[ Option[ Map[ String, List[ List[ String ] ] ] ] ]

val res = j.map { m ⇒
    val r = m get "result"
    r.map { ll ⇒
        ll.foldRight( List(): List[ Map[ String, String ] ] ) { ( l, acc ) ⇒
            Map( ( "Name" -> l( 0 ) ), ( "Val1" -> l( 1 ) ), ( "Val2" -> l( 2 ) ) ) :: acc
        }
    }.getOrElse(None) 
}.getOrElse(None) 

• Note 1: I had to put double quotes around result in the JSON String to get the JSON parser to work
• Note 2: the code could look nicer using more “monadic” sugar such as for comprehensions or using applicative functors