JSON Array

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

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

For example, given is a JSON document which contains a JSON array rights.

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

Get Value from Array

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

x = myObj.rights[0];

Program output.

admin

Delete Array Value

Use the delete keyword to delete items from an array:

delete myObj.rights[1];

Update Array Value

Use the index number to modify an array:

myObj.rights[1] = "blogger";

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

Multi-dimensional array

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

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

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