using Newtonsoft.Json.Linq;

using System;

using System.Collections.Generic;

using System.Linq;

​

string sampleJson = "{\"name\":{\"first\":\"Robert\",\"middle\":\"\",\"last\":\"Smith\"},\"age\":25,\"DOB\":\"-\"," +

    "\"hobbies\":[\"running\",\"coding\",\"-\"],\"education\":{\"highschool\":\"N\\/A\",\"college\":\"Yale\"}}";

JObject inputJson = JObject.Parse(sampleJson);

​

ICollection<string> jsonKeys = GetAllKeys(sampleJson);

​

foreach (string key in jsonKeys)

    RemoveJson(inputJson[key]!);

JObject cleanedJson = JObject.Parse(inputJson.ToString());

RemoveJsonFromRoot(inputJson, cleanedJson);

​

Console.WriteLine(cleanedJson);

​

ICollection<string> GetAllKeys(string json)

{

    ICollection<string> keys = new List<string>();

    var raw = JRaw.Parse(json);

    foreach (JProperty prop in raw.OfType<JProperty>())

    {

        keys.Add(prop.Name);

    }

    return keys;

}

​

static void RemoveJson(JToken node)

{

    foreach (var item in node)

    {

        if (item.HasValues)

        {

            string value = item.Last!.ToString();

            if (value == "" || value == "N/A" || value == "-")

            {

                item.Remove();

                break;

            }

        }

        else

        {

            if (item.Value<string>() == "" || item.Value<string>() == "N/A" || item.Value<string>() == "-")

            {

                item.Remove();

                break;

            }

        }

    }

}

​

static void RemoveJsonFromRoot(JObject inputJson, JObject cleanedJson)

{

    foreach (var jsonItem in from KeyValuePair<string, JToken> jsonItem in inputJson

                               where jsonItem.Value.ToString() == "" || jsonItem.Value.ToString() == "N/A" || jsonItem.Value.ToString() == "-"

                               select jsonItem)

    {

        cleanedJson.Remove(jsonItem.Key);

    }

}