Deserialize json in Dictionary<double, double[]>

Question

I need to store and read a Dictionary<double, double[]> in json. All links I found so far handles Dictionary<object,object>, not the case where the value is an Array. Is there a json-Syntax for this, like:

  "MyDic": {    
  "0":[90,270],
  "90":[0],
  "270":[0]    
  }

deserializes to Dictionary<string,double[]>, but

  "MyDic": {    
  0:[90,270],
  90:[0],
  270:[0]    
  }

is invalid json - obviously.

Do I need to save it as nested arrays, like

  "MyDic": [    
  [0,[90,270]],
  [90,[0]],
  [270,[0]]    
  ]

and convert it manually for serializing/deserializing?

Answer 1

This works OK:

var dict = new Dictionary<double, double[]>()
{
    [0] = new double[] { 0, 1, 2 },
    [1] = new double[] { 3, 4, 5 },
    [2] = new double[] { 6, 7, 8 }
};

string s = JsonConvert.SerializeObject(dict, Formatting.Indented);

Console.WriteLine(s);

dict = JsonConvert.DeserializeObject<Dictionary<double, double[]>>(s);

foreach (var entry in dict)
{
    Console.WriteLine($"{entry.Key}: {string.Join(", ", entry.Value)}");
}

The output is:

{
  "0": [
    0.0,
    1.0,
    2.0
  ],
  "1": [
    3.0,
    4.0,
    5.0
  ],
  "2": [
    6.0,
    7.0,
    8.0
  ]
}

And:

0: 0, 1, 2
1: 3, 4, 5
2: 6, 7, 8

(Tested with <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />)

What issues are you having?