How To Merge Two Json Objects or Files

Merge two JSON objects or files is an intermediate-level interview question, and sometimes interviewers may phrase it as ‘join,’ ‘combine,’ ‘concatenate,’ or ‘multiply’ two JSON objects. These terms might be used interchangeably to inquire about the process of merging JSON data.

Welcome back, visitors! In this article, I’m going to delve into the logic behind merging JSON objects. Join me as we explore the solution to concatenating two JSON strings in C#. I am going to cover how to join two json objects

Note for new users: If you have questions regarding your programming interview or if you’re stuck somewhere, I suggest joining our Quora Community. It’s free, and you’ll receive answers within 24 hours. If you are preparing for Beginner or Intermediate level Interview then do check our those tags.

What Is Json ?

It is crucial to understand what JSON is because without knowing its structure, you cannot create any logic to manipulate JSON data.

JSON stands for JavaScript Object Notation, which is a text format that humans can read. Below is an example of JSON:

{
  "name": "MergeTwoJson",
  "id": 2
}

How To Join Json Files Or Objects

Let’s delve into the heart of this article: Concatenating two JSON objects. I hope you are aware of what JSON is and how it works.

To combine multiple JSON objects, I’m going to use C#’s Dictionary. Using this, we can accomplish our merging within 3 steps.

We will store both JSON data into a dictionary and then use any JSON object converter library to create serialized versions of both JSON files.

Program To Merge Two Json Or Files

Allows’s initiate our implementation to merge two JSON objects or files.

Step 1

Firstly, we need to have two JSON objects or files. In our case, I’m going to create two JSON files and use the following JSON data to store in them.

// fileone.txt
{
  "name": "interviewspreparation.com",
  "id": 1
}

// filetwo.txt
{
  "name": "MergeTwoJson",
  "id": 2
}

Step 2

Now that we have two JSON objects, let’s write code to read both JSON files and store their contents in two JSON objects.

static void Main(string[] args)
{
    
    var jsonOne JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(PathFileOne));
    var jsonTwo JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(PathFileTwo));
    
}

As discussed in the above section, I’m going to use a Dictionary to combine two JSON objects. Therefore, I have used the ‘JsonConvert.DeserializeObject<Dictionary<string, object>>‘ code.

As well, I have used the Newtonsoft.Json library to deserialize JSON strings to a dictionary.

Step 3

Finally, I’m going to use those two objects to serialize them and create a JSON string. This will be our output, concatenating two JSON objects.

static void Main(string[] args)
{
    
    var jsonOne = JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(PathFileOne));
    var jsonTwo = JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(PathFileTwo));
    
    var jsonArray = new List<Dictionary<string, object>> { jsonOne, jsonTwo };

    string mergedJson = JsonConvert.SerializeObject(jsonArray);
    
    Console.WriteLine(mergedJson);
}

Alternatively, you can use an array to fetch your joined JSON objects.

static void Main(string[] args)
{
    
    var jsonOne = JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(PathFileOne));
    var jsonTwo = JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(PathFileTwo));
    
    var jsonArray = new List<Dictionary<string, object>> { jsonOne, jsonTwo };

    string mergedJson = JsonConvert.SerializeObject(jsonArray);
    
    Console.WriteLine(mergedJson);

    Profile[] profiles = JsonConvert.DeserializeObject<Profile[]>(mergedJson);

    foreach (var item in profiles)
    {
        Console.WriteLine(item.Id + " ___ " + item.Name);
    }
}

Program To Merge Multiple Json Objects or Files

Merging more than two JSON objects is not a big deal when you use the above code. You just need to change the two static objects to a loop and store each JSON into a list of dictionary, then serialize it. Check the code below to understand more.

static void Main(string[] args)
{
    List<Dictionary<string, object>> jsonArray = new List<Dictionary<string, object>>();
    
    string[] Paths = { PathFileOne, PathFileTwo, PathFileThree};

    foreach (string path in Paths)
    {
        var json = JsonConvert.DeserializeObject<Dictionary<string, object>>(File.ReadAllText(path));
        jsonArray.Add(json);
    }

    string mergedJson = JsonConvert.SerializeObject(jsonArray);

    Console.WriteLine(mergedJson);

    Profile[] profiles = JsonConvert.DeserializeObject<Profile[]>(mergedJson);

    foreach (var item in profiles)
    {
        Console.WriteLine(item.Id + " ___ " + item.Name);
    }
}

Summarizing Merge Two Json Or Multiple Json

Understanding JSON and Its Importance JSON, short for JavaScript Object Notation, serves as a lightweight data-interchange format widely used in modern programming. Its human-readable format and simplicity make it an ideal choice for data representation and exchange in various applications.

Merging JSON Objects in C# Using Dictionaries In C#, dictionaries offer a convenient approach for merging JSON objects. By deserializing JSON strings into dictionaries and merging them, developers can efficiently concatenate JSON data. Libraries like Newtonsoft.Json facilitate this process, providing robust serialization and deserialization capabilities.

Extending Merging Logic for Multiple JSON Objects To merge more than two JSON objects, developers can extend the merging logic by iterating through the objects dynamically. This scalable approach involves storing JSON data in dictionaries iteratively before serialization. By implementing this method, developers ensure flexibility and reusability in handling multiple JSON objects efficiently.