How to use json.net(JObject/Jarray/Jtoken) and convert to class in the fastest way into a dictionary?

Question

How to use json.net(JObject/Jarray/Jtoken) and convert to class in the fastest(performance) way into a dictionary? the key of the dictionary is the sees "name" in the json file

Can anyone help?

Thanks alot!

seed.json
       {
          "Seed": [
                {
                    "name": "Cheetone",
                    "growthrate": 1,
                    "cost": 500
                },
                {
                    "name": "Tortone",
                    "growthrate": 8,
                    "cost": 100
                }
            ],
        }


    public class SoilStat
    {
        public int growthRate;
        public int cost;
    }

    public class DataLoader : MonoSingleton<DataLoader>
    {
        public string txt;
        Dictionary<string, SoilStat> _soilList = new Dictionary<string, SoilStat>();

        JObject rawJson = JObject.Parse(txt);

        ???
    }

What is `_txtAsset`? Is it that snippet of JSON at the top? If so, can you please provide the actual valid JSON you are using? (as it is, it's malformed) — Kirk Woll, Dec 15 '15 at 01:24
Your question sounds very general but the actual code you show seems not to be so. What are the dictionary keys supposed to be? — dbc, Dec 15 '15 at 01:24
By "fastest" do you mean "most performant" or "most straightforward"? — dbc, Dec 15 '15 at 01:54
Then I may point you to [Which is faster?](http://ericlippert.com/2012/12/17/performance-rant/) by [Eric Lippert](http://stackoverflow.com/users/88656/eric-lippert). I can give you a very simple way to do what you want but you'll need to do performance testing yourself. Want it? — dbc, Dec 15 '15 at 01:57

score 2 · Answer 1 · edited May 23 '17 at 12:25

A simple way to do what you want is to use SelectTokens to pick out the portions of JSON of interest to you, then just deserialize those bits. Thus:

        var rawJson = JObject.Parse(txt);
        var _soilList = rawJson.SelectTokens("Seed[*]").ToDictionary(t => t["name"], t => t.ToObject<SoilStat>());

A more complex solution would be to create DTO objects for deserialization then map them to your desired classes:

public class NamedSoilStat : SoilStat
{
    public string name { get; set; }
}

public class RootObject
{
    public RootObject() { this.Seed = new List<NamedSoilStat>(); }
    public List<NamedSoilStat> Seed { get; set; }
}

And then:

        var root = JsonConvert.DeserializeObject<RootObject>(txt);
        var _soilList = root.Seed.ToDictionary(t => t.name, t => new SoilStat { cost = t.cost, growthRate = t.growthRate });

As to which is more performant, you would need to test for yourself.

Incidentally, if your txt JSON string is coming from a file, and is large, you should consider streaming it in rather than reading it into an intermediate string. See Performance Tips: Optimize Memory Usage.

I cant use selecttoken due to some restriction on unity5. is there other way to do it without creating DTO object? @dbc — phongyewtong, Dec 27 '15 at 04:09

score 1 · Answer 2 · answered Dec 15 '15 at 01:47

1

In my experiences, using JsonConvert is significantly faster than using JObject.Parse(). See this page for a performance comparison (on Windows Phone, but I'd imagine it would be similar on desktop), and linked from that page is an example that uses JsonConvert.

answered Dec 15 '15 at 01:47

gregstoll

1,318
9
14

thanks but how do i use JsonConvert.DeserializeObject into dictionary with seed "name" as the key? – phongyewtong Dec 15 '15 at 01:51

How to use json.net(JObject/Jarray/Jtoken) and convert to class in the fastest way into a dictionary?

2 Answers2

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