How to write json array

How to write json array: 1. Use [for-in] to access the array; 2. Use the index value to modify the array value; 3. Use the delete keyword to delete the array element, the code is [delete myObj. sites[1];].

#The operating environment of this article: Windows 7 system, Dell G3 computer.

How to write json array:

Array as JSON object

[ "Google", "Runoob", "Taobao" ]

JSON array in Written in brackets.

Array values ​​in JSON must be legal 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.

Array in JSON object

The value of the object property can be an array:

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

We can use the index value to access the array:

x = myObj.sites[0];

Looping through an array

You can use for-in to access an array:

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

You can also use a for loop:

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

Arrays in nested JSON objects

The array in the JSON object can contain another array, or another JSON object:

myObj = {
    "name":"网站",
    "num":3,
    "sites": [
        { "name":"Google", "info":[ "Android", "Google 搜索", "Google 翻译" ] },
        { "name":"Runoob", "info":[ "菜鸟教程", "菜鸟工具", "菜鸟微信" ] },
        { "name":"Taobao", "info":[ "淘宝", "网购" ] }
    ]
}

We can use for-in to loop Access each array:

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

Modify the array value

You can use the index value to modify the array value:

myObj.sites[1] = "Github";

Delete the array element

We can use the delete keyword to delete array elements:

delete myObj.sites[1];

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