JSON Format Tutorial
JSON, or JavaScript Object Notation, is a lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate. JSON is a text format that is completely language-independent but uses conventions familiar to programmers of the C family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others.
Example
{
"name": "Alice Smith",
"age": 30,
"email": "[alice.[email protected]](<mailto:[email protected]>)",
"isStudent": false,
"courses": ["math", "history", "chemistry"],
"address": {
"street": "123 Main St",
"city": "New York",
"state": "NY",
"zipCode": "10001"
}
}
In this JSON example:
- The person's name, email, and address fields are strings.
- The age is a number.
- The isStudent field is a boolean.
- The courses field is an array of strings.
- The address field is an object containing the street, city, state, and zipCode fields
JSON is often used to transmit data between a server and a web application, serving as an alternative to XML. JSON is favored because it is:
- Easy to read and write for humans
- Easy to parse and generate for machines
- Less verbose than XML
- Natively supported in JavaScript
- Widely supported in many programming languages
JSON syntax is a set of rules for writing JSON data. JSON data is represented using two structures:
- 1.A collection of key-value pairs (also known as an object)
- 2.An ordered list of values (also known as an array)
The key features of JSON syntax are:
- Data is stored in key-value pairs, separated by colons (
:
) - Curly braces (
{}
) hold objects - Square brackets (
[]
) hold arrays - Keys must be strings wrapped in double quotes (
"
) - Values can be strings, numbers, booleans, objects, or arrays
- Multiple key-value pairs in an object, as well as multiple values in an array, are separated by commas (
,
)
JSON supports the following data types:
String: A sequence of characters enclosed in double quotes, e.g.,
"hello"
Number: A number without quotes, e.g.,
42
or 3.14
. JSON numbers can be integers or floating-point values.Boolean: Represents either
true
or false
(without quotes)Array: An ordered collection of values enclosed in square brackets, e.g.,
["apple", "banana", "cherry"]
Object: A collection of key-value pairs enclosed in curly braces, e.g.,
{"name": "John", "age": 30}
null: Represents an empty value or non-existence (without quotes)
A JSON object is a collection of key-value pairs, where each key is a string, and the value can be any JSON data type. JSON objects are wrapped in curly braces (
{}
). For example:jsonCopy code
{
"name": "John Doe",
"age": 35,
"isStudent": false
}
A JSON array is an ordered collection of values, where each value can be any JSON data type. JSON arrays are wrapped in square brackets (
[]
). For example:jsonCopy code
[
{
"name": "John Doe",
"age": 35,
"isStudent": false},
{
"name": "Jane Doe",
"age": 28,
"isStudent": true
}
]
Last modified 2mo ago