JSON Arrays

Arrays in JSON are almost the same as arrays in JavaScript. In JSON, array values must be of type string, number, object, array, boolean or null.

Example

["Audi", "BMW", "Ferrari"]

Arrays in JSON Objects

Arrays can be values of an object property.

Example

{
	"name": "John",
	"age": 32,
	"cars": ["Audi", "BMW", "Ferrari"]
}

Accessing Array Values

You access the array values by using the index number just like javascript arrays.

Example

x = jsonObj.cars[0];

Sample JSON array objects.

snippet

//JSON Array of Strings
["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"] 

//JSON Array of Numbers
[12, 34, 56, 43, 95]   

//JSON Array of Booleans
[true, true, false, false, true]  

//JSON Array of Objects
{"employees":[   
    {"name":"Ram", "age":23},   
    {"name":"Shyam", "age":28}, 
    {"name":"John", "age":33},   
    {"name":"Bob", "age":41}  
]}

//JSON Multidimensional Array
[   
    [ "a", "b", "c" ],  
    [ "m", "n", "o" ],  
    [ "x", "y", "z" ]  
]

Looping Through an Array

You can access array values by using a for-in loop or for loop.

Example

for (i in jsonObj.cars) {
    x += jsonObj.cars[i];
}

Using for loop

Example

for (i = 0; i < jsonObj.cars.length; i++) {
    x += jsonObj.cars[i];
}

Nested Arrays in JSON Objects

Values in an array can also be another array, or even another JSON object.

snippet

jsonObj = {
    "name":"John",
    "age":30,
    "cars": [
        { "name":"Audi", "models":[ "A3 Sportback", "A4", "Q4" ] },
        { "name":"BMW", "models":[ "X5", "320", "X3" ] },
        { "name":"Ferrari", "models":[ "512 TR", "488 GTB", "360 Modena" ] }
    ]
}

To access arrays inside arrays, use a for-in loop for each array.

Example

for (i in jsonObj.cars) {
    x += "<h2>" + jsonObj.cars[i].name + "</h2>";
    for (j in jsonObj.cars[i].models) {
        x += jsonObj.cars[i].models[j];
    }
}

Modify Array Values

Use the index number to modify an array.

jsonObj.cars[1] = "Mercedes";

Delete Array Items

Use the delete keyword to delete items from an array.

Example

delete jsonObj.cars[1];