CODEWITHSUNDEEP
javakotlin
khd
khd

Reputation: 1666

How to transform the Array of object to an object in Kotlin

I have a list of object

temp (1_id='I4509635', 2_id='I4406660', 3_id='I1111')
temp (1_id='I4509635', 2_id='I4406660', 3_id='I2222')
temp (1_id='I4509635', 2_id='I4406660', 3_id='I3333')  
temp (1_id='I4509635', 2_id='I1222233', 3_id='I14444')

and want to transform the list to an object. Like

"cat": [
    { "id_": "I4509635",
      "children": [
        {
          "id_": "I4406660",
          "children": [
            {
              id : [ "I1111", "I2222", "I3333"]
            }
          ]
        },
        {
          "id_": "I1222233",
          "children": [
            {
              "id: [ "I14444"]
            }
          ]
        }
      ]
    }
  ]

Upvotes: 0

Views: 118

Answers (1)

lukas.j
lukas.j

Reputation: 7172

I'm not sure I understand your question, you result object is neither a valid Kotlin object nor valid JSON.

data class Ftemp(val Wert_1_id: String, val Wert_2_id: String, val Wert_3_id: String)

val list = listOf(
  Ftemp("I4509635", "I4406660", "I1111"),
  Ftemp("I4509635", "I4406660", "I2222"),
  Ftemp("I4509635", "I4406660", "I3333"),
  Ftemp("I4509635", "I1222233", "I14444")
)

This will give you the data structured in the same way as in your post:

val result = list
  .groupBy { it.Wert_1_id }
  .map { (key, value) -> key to value
    .map { it.Wert_2_id to it.Wert_3_id }
    .groupBy { it.first }
    .map { (key, value) -> key to value.map { it.second } }
  }

This will give you the data structured in the same way as in your post, but with the maps indicating ids and children:

val cat = list
  .groupBy { it.Wert_1_id }
  .map { (key, value) ->
    mapOf(
      "id_" to key,
      "children" to value
        .map { it.Wert_2_id to it.Wert_3_id }
        .groupBy { it.first }
        .map { (key, value) ->
          mapOf(
            "id_" to key,
            "children" to mapOf("id" to value.map { it.second })
          )
        }
    )
  }

Upvotes: 1

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