JSON Array

1. Array Datatype in JSON

Similar to other programming languages, a JSON Array is a list of items surrounded in square brackets ([]). Each item in the array is separated by a comma.

• The array index begins with 0.
• The square brackets [...] are used to declare JSON array.
• JSON array are ordered list of values.
• JSON arrays can be of multiple data types.
• JSON array can store string, number, boolean, object or other array inside JSON array.
• In JSON array, values must be separated by comma.
• Arrays in JSON are almost the same as arrays in JavaScript.

For example, given below is a JSON document that contains a JSON array of access rights.

{
	"name" : "Admin",
	"age" : 36,
	"rights" : [ "admin", "editor", "contributor" ]
}

2. Array Operations

2.1. Get Value from Array

You can access the array values by using the index number:

x = myObj.rights[0];

Program output.

admin

2.2. Delete Array Value

Use the delete keyword to delete items from an array:

delete myObj.rights[1];

2.3. Update Array Value

Use the index number to modify an array:

myObj.rights[1] = "blogger";

2.4. Looping through Array Values

We can access array values by using a for-in loop:

for (i in myObj.rights) 
{
	x = myObj.rights[i];
	console.log(x);
}

Program output.

admin
editor
contributor

3. Multi-dimensional Arrays

3.1. Creating a multi-dimensional array

We can store an array inside another JSON array. It is known as an array of arrays or a multi-dimensional JSON array.

var siteInfo = {
	"name" : "blogger",
	"users" : [
		[ "admins", "1", "2" , "3"],
		[ "editors", "4", "5" , "6"],
	]
}

3.2. Iterating over multi-dimensional array

A simple for loop to iterate over a multi-dimensional array in JSON.

for (i in siteInfo .users) 
{
	for (j in siteInfo.users[i]) 
	{
		x = siteInfo.users[i][j];
		console.log(x);
	}
}

Program Output:

admins
1
2
3
editors
4
5
6