C# flattening json structure

Question

I have a json-object in C# (represented as a Newtonsoft.Json.Linq.JObject object) and I need to flatten it to a dictionary. Let me show you an example of what I mean:

{     "name": "test",     "father": {          "name": "test2"          "age": 13,          "dog": {              "color": "brown"          }     } } 

This should yield a dictionary with the following key-value-pairs:

["name"] == "test", ["father.name"] == "test2", ["father.age"] == 13, ["father.dog.color"] == "brown" 

How can I do this?

Answer 1

JObject jsonObject=JObject.Parse(theJsonString); IEnumerable<JToken> jTokens = jsonObject.Descendants().Where(p => !p.HasValues); Dictionary<string, string> results = jTokens.Aggregate(new Dictionary<string, string>(), (properties, jToken) =>                     {                         properties.Add(jToken.Path, jToken.ToString());                         return properties;                     }); 

I had the same requirement of flattening a nested json structure to a dictionary object. Found the solution here.

Answer 2

As of .NET Core 3.0 JsonDocument is a way (Json.NET is not needed). I'm sure this will get easier.

using System.Linq; using System.Text.Json; (...)   public static Dictionary<string, JsonElement> GetFlat(string json) {     IEnumerable<(string Path, JsonProperty P)> GetLeaves(string path, JsonProperty p)         => p.Value.ValueKind != JsonValueKind.Object             ? new[] { (Path: path == null ? p.Name : path + "." + p.Name, p) }             : p.Value.EnumerateObject() .SelectMany(child => GetLeaves(path == null ? p.Name : path + "." + p.Name, child));      using (JsonDocument document = JsonDocument.Parse(json)) // Optional JsonDocumentOptions options         return document.RootElement.EnumerateObject()             .SelectMany(p => GetLeaves(null, p))             .ToDictionary(k => k.Path, v => v.P.Value.Clone()); //Clone so that we can use the values outside of using } 

A more expressive version is shown below.

Test

using System.Linq; using System.Text.Json; (...)  var json = @"{     ""name"": ""test"",     ""father"": {             ""name"": ""test2"",           ""age"": 13,          ""dog"": {                 ""color"": ""brown""          }         }     }";  var d = GetFlat(json); var options2 = new JsonSerializerOptions { WriteIndented = true }; Console.WriteLine(JsonSerializer.Serialize(d, options2)); 

Output

{   "name": "test",   "father.name": "test2",   "father.age": 13,   "father.dog.color": "brown" } 

More expressive version

using System.Linq; using System.Text.Json; (...)  static Dictionary<string, JsonElement> GetFlat(string json)     {         using (JsonDocument document = JsonDocument.Parse(json))         {             return document.RootElement.EnumerateObject()                 .SelectMany(p => GetLeaves(null, p))                 .ToDictionary(k => k.Path, v => v.P.Value.Clone()); //Clone so that we can use the values outside of using         }     }       static IEnumerable<(string Path, JsonProperty P)> GetLeaves(string path, JsonProperty p)     {         path = (path == null) ? p.Name : path + "." + p.Name;         if (p.Value.ValueKind != JsonValueKind.Object)             yield return (Path: path, P: p);         else             foreach (JsonProperty child in p.Value.EnumerateObject())                 foreach (var leaf in GetLeaves(path, child))                     yield return leaf;     }