Parsing JArray from Json string?

Question

I want to parse a JArray from a Json String. For that I have this code:

        JObject myjson = JObject.Parse(theJson);
        JArray nameArray = JArray.Parse(theJson);                 
        _len = nameArray.Count();

The theJsonString is the following

"{\"0\": [-26.224264705882351, 0.67876838235294112, -38.031709558823529, 46.201555361781679],
  \"1\": [-26.628676470588236, 2.4784007352941178, -37.377297794117645, 45.959670050709867]}"

The problem is that when I debug I have nameArray always null and _len=0. Can you help to find the error.

http://stackoverflow.com/questions/26270990/how-to-parse-json-objects-with-numeric-keys-using-javascriptserializer — CodeCaster, Jul 05 '16 at 10:42

Abhay Dixit · Answer 1 · 2016-07-05T10:57:28.603

3

FYI Count is not a method, it is a property. Added below an example so use like this.

string json = @"
    [ 
        { ""test1"" : ""desc1"" },
        { ""test2"" : ""desc2"" },
        { ""test3"" : ""desc3"" }
    ]";

    JArray a = JArray.Parse(json);
     var _len = a.Count;

Here you will get value of _len = 3

edited Jul 05 '16 at 10:57

answered Jul 05 '16 at 10:44

Abhay Dixit

998
8
28

score 1 · Accepted Answer · answered Jul 05 '16 at 12:15

Your Json is invalid

valid Json

{"0": [-26.224264705882351, 0.67876838235294112, -38.031709558823529, 46.201555361781679],
  "1": [-26.628676470588236, 2.4784007352941178, -37.377297794117645, 45.959670050709867]}

Use this code to deserialize json

    var myjson = JsonConvert.DeserializeObject <Dictionary<int, double[]>>(theJson);
int _len = myjson.Count;

score 0 · Answer 3 · answered Jul 05 '16 at 10:50

Here you can't parse your json into a JArray. But you can use the JsonObject just like an array if you want to keep your json string.

Here is some bad code, but it can give you some ideas, i assume that the number in your json string is some ID and start to 0 to X :

        //Your json, the id is the value 0..1..2
        string json = "{\"0\": [-26.224264705882351, 0.67876838235294112, -38.031709558823529, 46.201555361781679],
                         \"1\": [-26.628676470588236, 2.4784007352941178, -37.377297794117645, 45.959670050709867]}";

        //Create json object
        JObject myjson = JObject.Parse(json);

        //Get the number of different object that you want to get from this json
        int count = getCountMyJson(myjson);

        //Create your Jarray
        JArray nameArray = new JArray();

        //Get the value from the json, each different value , start to 0 and going to the maximum value
        for (int i = 0; i < count; i++)
        {
           if(myjson[i+""] != null)
            nameArray.Add(myjson[i + ""]);
        }
        //Now you have a JArray that match all your json value ( here the object 0 and 1)

Here is a bad function ( bad code, while is disgusting) but it works and you can understand what you can do with it ( assuming the id is 0 to XXX ) :

 public static int getCountMyJson(JObject json)
    {
        int i = 0;
      while(json.GetValue(i+"") != null)
        { i++; }
        return i;
    }

Parsing JArray from Json string?

3 Answers3