How to query multiple fields from json string?

Question

I have the following json string:

[
    {
        "id": 1,
        "type": "bird",
        "includeorexclude": "include"        
    },
    {
        "id": 2,
        "type": "animal",
        "includeorexclude": "include"       
    },
    {
        "id": 3,
        "type": "animal",
        "includeorexclude": "exclude"       
    }
]

And here is the code to select type from each json object:

var queries = JArray.Parse(json);
var queryTypes = queries.SelectTokens("$..type")
                        .Select(x => x.Value<string>())
                        .ToList();


foreach (var type in queryTypes)
{
    // var message = CreateMessage();
    // message.UserProperties.Add("Type", type);    
}

How do I get both type and includeorexclude from each json object?

Serge · Accepted Answer · 2022-07-28 00:24:51Z

2

you can use an anonymos type

    var jsonParsed = JArray.Parse(json);

    var queryTypes = jsonParsed.Select(x => new
    {
        type = (string)x["type"],
        includeorexclude = (string)x["includeorexclude"]
    }
    ).ToList();

    foreach (var type in queryTypes)
    {
        Console.WriteLine(type.type);
        Console.WriteLine(type.includeorexclude);
    }

or create a class instead of an anonymous type

answered Jul 28, 2022 at 0:24

Serge

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5 Comments

user989988 Over a year ago

What if the includeorexclude property has a boolean value? How do I update this?

Serge Over a year ago

@user989988 replace (string) by (bool)

user989988 Over a year ago

I see this error on replacing : ?? can not be applied to operands of type bool and bool

Serge Over a year ago

@user989988 I don't have any ??

user989988 Over a year ago

Sorry to give you more context - I updated the code to includeorexclude = (string)x["includeorexclude"] ?? "include" to provide a default value on updating this to includeorexclude = (bool)x["includeorexclude "] ?? false I get the above error

Emopusta · Accepted Answer · 2022-07-28 20:07:04Z

0

You can just create a class that has properties type and includeorexclude. Then you create new objects with that class and assign your data with your query. After that a generic list can contain all you need.

I think words are not enough for the solution here my perspective about this question.

This is my main class that does the job:

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace stackoverflow
{
    internal class Program
    {
        static void Main(string[] args)
        {
            using (StreamReader r = new StreamReader("stack1.json"))
            {
                // some convertion and reading from json file
                string json = r.ReadToEnd();
                List<Item> items = JsonConvert.DeserializeObject<List<Item>>(json);

                // do your query here with linq
                var result = items.Select(x => x).ToList();

                //writing result
                foreach (var item in result)
                {
                    Console.WriteLine(item.type);
                    Console.WriteLine(item.includeorexclude);
                   
                }
            }
            
        }
    }
}

and this is the class that i told you add properties that you needed.

// Item that includes what is in json file
    internal class Item
    {
        public int id { get; set; }
        public string type { get; set; }
        public string includeorexclude { get; set; }
    }

I hope this helps you to understand what i meant.

edited Jul 28, 2022 at 20:07

answered Jul 27, 2022 at 23:36

Emopusta

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3 Comments

Enigmativity Over a year ago

Please show us how this is done in code.

Enigmativity Over a year ago

Much better with code. Why are you doing this, though? var result = items.Select(x => x).ToList();

Emopusta Over a year ago

The question was using .Select. I just added useless query line to show example that you can do queries here.

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