What is JSON?

What is JSON?

JSON stands for JavaScript Object Notation, is a lightweight format for exchanging and storing data. The format of data storage is mostly used in REST API calls (the REST request and response) and in NoSQL Databases like MongoDB. JavaScript Object Notation as a format is very straight forward, self-describing and intuitive.

Definition

It is the same as the format in which the JavaScript objects are created but in JSON, the objects are rather texting only. Reading and generating JavaScript Object Notation can be done using any programming language. We might have to follow the following syntax rules –

1. The data is always in key/value pairs.
2. Every data object is separated by a comma.
3. The objects are held within the curly braces (the flower bracket like this ‘{}’)
4. The arrays are held in square brackets.

JSON object

A typical object is as follows

{
“Name”: “Alex”,
“Occupation”: “Teacher”,
“Places visited”: [“San Francisco”, “California”, “Houston”] }

In the above examples, ‘Name’, ‘Occupation’, ‘Places visited’ are the keys and ‘’Alex’, ‘Teacher’ and the array [“San Francisco”, “California”, “Houston”] are the values of the respective keys and the whole data enclosed in the flower brackets constitutes an JavaScript Object Notation Object. The values can be a string, another object, a Boolean, null, a number.
The objects can also be nested and also be in the form of arrays.

Examples:

1. Nested objects

{
“Role”: “Student”,
“Name”: {
“First name”: “Alex”,
“Last name”: “Hill”
}
}

The outer curly braces form the primary JSON object nesting to another JSON object with the key ‘Name’ followed by the data in the inner curly braces. Next, let’s see the array of objects.

2. An array of objects

{
“Grade”: 6,
“Student names”: [
{
“First name”: “Alex”,
“Last name”: “Hill”
},
{
“First name”: “Neal”,
“Last name”: “Hunter”
},
{
“First name”: “Peter”,
“Last name”: “Jones”
}
] }

As you can see, the outer curly braces form the primary JSON data object and there is a square bracket pair that encloses a set of objects which is the array of JSON objects.

3. Datatypes

Values must have one of the following datatypes.

• Strings:

{“name”: “Johnny”}

• Number:

{“age”: 21}

• Object:

{
“employee”: {“name”: “John”, “age”: 221}
}

Note – The objects in the JSON objects that are nested must also follow the same syntax rules as that of a normal JSON object.

• Boolean:

{“sale”: true}

4. JSON Parsing

Let us consider Python as the example programming language and see how to handle the data objects.

1. import json
# json is the module in python to handle its data objects

2. string_a = “{“name”: “Alex”, “age”: “22”, “occupation”: “Teacher”}”
# let me explain the example of string format with the syntax rules

3. json_object = json.loads(string_a)
# now the json_object has the string_a as the JSON object and the key values can be referred like the following

print(“The name is”, json_object[“name”])
print(json_object[“name”, “’s age is”, json_object[‘age’]])

So, in JSON parsing using python, the JSON objects take the form of a dictionary and the keys will be referred to in the index as mentioned in the above example.

Now let us see how we can parse the JSON objects from a file in Python

1. import json
# json is the module in python to handle its objects

2. file_handler = open(‘json_data_file.json’, ‘r’)
# open is the function to open a file in python and the json files are stored with the extension
# .json which in this example is opened in reading mode ‘r’

3. json_object = json.load(file_handler)
# json.load() is the function that accepts the file handler of the json file and reads its data
# objects from the file
print(“The name is”, json_object[“name”])
print(json_object[“name”, “’s age is”, json_object[‘age’]])

Note – You can either read the file, extract the content as string & use json.loads() method to get the json object or directly use the load method to extract passing the file handler as the parameter

Exchange of data objects

Almost all the programming languages are powered to generate and handle dictionaries or hashes or associative arrays. So, the data that needs to be exchanged between the clients and the servers need to be typecast to one of these forms depending on the programming language being used.

JSON vs XML

Traditionally, the protocol used to exchange data between the client and the server was SOAP (Simple Object Access Protocol) that used XML (Extensible Markup Language). With the introduction of REST (Representational State Protocol) the use of JavaScript Object Notation became widely famous.

Here are a few similarities between them

1. Both are intuitive and easy to read.
2. Both can be nested and hierarchical.
3. Both can be parsed using a wide variety of languages.
4. Both are exchanged over web requests for data transfer.

Here are a few differences between them

1. It has no tag format.
2. It is storage optimal as it is relatively shorter than XML.
3. It is faster to read and write.
4. It can use arrays while it is not easy in XML.

Disadvantages

While we saw the advantages, it is not devoid of disadvantages too. Following are the disadvantages:

1. It is not fully secure.
2. It is limited in terms of the supported datatypes.

How knowledge regarding JSON will help you in your career?

It is a data format that is used to exchange information between clients and servers. Imagine, if you could develop an optimized schema for data representation that uses fewer data to exchange large data then that is a great thing. The whole world is moving towards RESTful API services. Which is why having a great deal with this language will help you to come up with cool API services.

Conclusion

It is one of the cool data formats for accessing, storing and comprehending data. If you are looking for something that is quick, lightweight for data exchange, then you can always look forward to employing JavaScript Object Notation.

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