CODEWITHSUNDEEP
kotlingson
sri
sri

Reputation: 73

How to check number of times JSON element occurrence in JSON objects of JsonArray in Kotlin?

[
  {
    "ReserveNumber": "RN001",
    "RecordType": "Bsdfs",
    "RequireType": "BBsdfdsdf"
  }, {
    "ReserveNumber": "RN002",
    "RecordType": "Breer",
    "RequireType": "BBertert"
  }, {
    "ReserveNumber": "RN001",
    "RecordType": "Brete",
    "RequireType": "BBdvdv"
  }, {
    "ReserveNumber": "RN003",
    "RecordType": "Berretert",
    "RequireType": "BBxcvvd"
  }
]

In the above JSON array, each JSON object contains ReserveNumber element. Here how to find the count of reservation number if it occurs multiple times? Here ReserveNumber RN001 occurred twice. How to find it using GSON library in Kotlin?

Upvotes: 0

Views: 606

Answers (2)

terrorrussia-keeps-killing
terrorrussia-keeps-killing

Reputation: 1787

I don't do Kotlin, but it seems to be pretty easy in Kotlin (and even simpler than using Java 8 Streams API):

fun group(input: JsonArray): JsonArray {
    return input.map { it.getAsJsonObject().getAsJsonPrimitive("ReserveNumber").asString }
            .groupingBy { it }
            .eachCount()
            .entries
            .fold(JsonArray(), { jsonArray, e ->
                val el = JsonObject()
                el.addProperty("key", e.key)
                el.addProperty("count", e.value)
                jsonArray.add(el)
                jsonArray
            })
}

The function above is not generic and can be improved if necessary, but now for your JSON document it can produce the following JSON array (similar to what you've referred to: How to get repeated objects in json array in javascript in your first comment, but with another output JSON object property names):

[
    {"key": "RN001", "count": 2},
    {"key": "RN002", "count": 1},
    {"key": "RN003", "count": 1}
]

Upvotes: 1

Ahmad Sattout
Ahmad Sattout

Reputation: 2476

You can do it in a couple of ways. But the most simple one is using GSON itself

  • 1- Build a class that represents your JSON object

  • 2- Build a Map<String, Int> that represents the ReserveNumber and the count

  • 3- Iterate through the objects and add to the count

Upvotes: 1

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