JSON (JavaScript Object Notation) Basics

JSON is a text-based, standard data format used for storing and transmitting data. While it originated from JavaScript object literal notation, it is now language-agnostic and universally used across programming platforms.

It is the de facto standard format for data exchange in modern web APIs.

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1. JSON Structure

JSON builds data using two fundamental structures:

① Object

Represented by curly braces { }, an object is an unordered collection of key-value pairs. The key must always be a string.

{
    "firstName": "John",
    "lastName": "Doe",
    "age": 45,
    "isStudent": false
}

② Array

Represented by square brackets [ ], an array is an ordered list of values. These values can be any valid JSON type: string, number, boolean, object, or another array.

[
    "Red",
    "Green",
    "Blue",
    123
]

3. Nested Structure Example

JSON's flexibility comes from its ability to nest objects and arrays within each other.

{
    "userID": 42,
    "orders": [
        {
            "productName": "Keyboard",
            "quantity": 1
        },
        {
            "productName": "Monitor",
            "quantity": 2
        }
    ],
    "totalItems": 3
}

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2. Importance and Advantages

1. Lightweight: JSON is minimal and less verbose than formats like XML, leading to smaller data sizes and faster transmission.
2. Readability: It is easy for humans to read and write.
3. Universal Compatibility: Almost all modern programming languages (Python, JavaScript, Java, etc.) have built-in functions to easily serialize (create) and parse (read) JSON data.