What is JSON

What is JSON?

JSON (JavaScript Object Notation) is a compact, text based format for computers to exchange data. The official Internet media type for JSON is application/json, and the JSON filename extension is .json

JSON is built on two structures:

A collection of name/value pairs
An ordered list of values.

JSON take these forms: objects, array, value, string, number

Object

Unordered set of name/value pairs. Begins with { and ends with }. Each name is followed by : (colon) The name/value pairs are separated by , (comma).

Array

Ordered collection of values. Begins with [ and ends with ]. Values are separated by , (comma).

Value

Can be a string in double quotes, number, or true or false or null, or an object or an array.

String

A sequence of zero or more Unicode characters, wrapped in double quotes, using backslash escapes.

Number

Integer, long, float

The following example shows the JSON representation of an object that describes a person:

{
    "firstName": "John",
    "lastName": "Smith",
    "age": 25,
    "address": {
        "streetAddress": "21 2nd Street",
        "city": "New York",
        "state": "NY",
        "postalCode": "10021"
    },
    "phoneNumber": [
        {
            "type": "home",
            "number": "212 555-1234"
        },
        {
            "type": "fax",
            "number": "646 555-4567"
        }
    ]
}

JSON data structures map directly to Python data types, so this is a powerful tool for directly accessing data without having to write any XML parsing code. JSON is once loaded into Python just like a dictionary.