JSON Arrays

Arrays as JSON Objects

Example

[ "Google", "tutorialpro", "Taobao" ]

JSON arrays are written inside square brackets.

Square brackets [] hold arrays which are ordered collections of values. An array begins with a left square bracket [ and ends with a right square bracket ], with values separated by commas ,.

In JSON, array values must be of valid JSON data types (string, number, object, array, boolean, or null).

In JavaScript, array values can be the above JSON data types, or JavaScript expressions, including functions, dates, and undefined.

Arrays in JSON Objects

The value of an object property can be an array:

Example

{
"name":"网站",
"num":3,
"sites":[ "Google", "tutorialpro", "Taobao" ]
}

We can access array elements using their index values:

Example

x = myObj.sites[0];

Looping Through Arrays

You can use a for-in loop to access array elements:

Example

for (i in myObj.sites) {
    x += myObj.sites[i] + "<br>";
}

You can also use a for loop:

Example

for (i = 0; i < myObj.sites.length; i++) {
    x += myObj.sites[i] + "<br>";
}

Arrays in Nested JSON Objects

Arrays in JSON objects can contain another array or another JSON object:

Example

myObj = {
    "name":"网站",
    "num":3,
    "sites": [
        { "name":"Google", "info":[ "Android", "Google 搜索", "Google 翻译" ] },
        { "name":"tutorialpro", "info":[ "tutorialpro.org", "tutorialpro", "geek" ] },
        { "name":"ebay", "info":[ "good", "network" ] }
    ]
}

We can use a for-in loop to iterate through each array:

Example

for (i in myObj.sites) {
    x += "<h1>" + myObj.sites[i].name + "</h1>";
    for (j in myObj.sites[i].info) {
        x += myObj.sites[i].info[j] + "<br>";
    }
}

Modifying Array Values

You can modify array values using their index values:

Example

myObj.sites[1] = "Github";

Deleting Array Elements

We can use the delete keyword to remove array elements:

Example

delete myObj.sites[1];