一篇文章帶你了解 JavaScript json 數(shù)組
簡(jiǎn)單說(shuō)，所謂對(duì)象，就是一種無(wú)序的數(shù)據(jù)集合，由若干個(gè)“鍵值對(duì)”（key-value）構(gòu)成。
一、數(shù)組作為JSON對(duì)象
[ "Ford", "BMW", "Fiat" ]在JSON中的數(shù)組，幾乎和在JavaScript中數(shù)組相同。
在JSON中，數(shù)組的值必須是字符串，數(shù)字、對(duì)象、數(shù)組、布爾值或空.
JavaScript中，數(shù)組的值可以是以上所有，再加上其他任何有效的JavaScript表達(dá)式，包括函數(shù)、日期、和undefined。
二、JSON對(duì)象中的數(shù)組
數(shù)組可以是對(duì)象屬性的值:
{
"name":"John",
"age":30,
"cars":[ "Ford", "BMW", "Fiat" ]
}1. 訪問(wèn)數(shù)組的值
使用索引號(hào)訪問(wèn)數(shù)組值:
x = myObj.cars[0];完整代碼：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>項(xiàng)目</title>
</head>
<body style="background-color: aqua;">
<p id="demo"></p>
<script>
myObj = {
"name": "John",
"age": 30,
"cars": ["Ford", "BMW", "Fiat"]
}
x = myObj.cars[0];
document.getElementById("demo").innerHTML = x;
</script>
</body>
</html>
2. 遍歷數(shù)組
你可以使用for-in循環(huán)遍歷數(shù)組:
for (i in myObj.cars) {
x += myObj.cars[i];
}或者可以使用for循環(huán):
for (i = 0; i < myObj.cars.length; i++) {
x += myObj.cars[i];
}
三、JSON對(duì)象中的嵌套數(shù)組
數(shù)組值也可以是另一個(gè)數(shù)組，甚至另一個(gè)JSON對(duì)象:
myObj = {
"name":"John",
"age":30,
"cars": [
{ "name":"Ford", "models":[ "Fiesta", "Focus", "Mustang" ] },
{ "name":"BMW", "models":[ "320", "X3", "X5" ] },
{ "name":"Fiat", "models":[ "500", "Panda" ] }
]
}訪問(wèn)數(shù)組內(nèi)部的數(shù)組, 使用for-in loop循環(huán):
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>項(xiàng)目</title>
</head>
<body style="background-color: aqua;">
<p>Looping through arrays inside arrays.</p>
<p id="demo"></p>
<script>
var myObj, i, j, x = "";
myObj = {
"name":"John",
"age":30,
"cars": [
{ "name":"Ford", "models":[ "Fiesta", "Focus", "Mustang" ] },
{ "name":"BMW", "models":[ "320", "X3", "X5" ] },
{ "name":"Fiat", "models":[ "500", "Panda" ] }
]
}
/*訪問(wèn)數(shù)組內(nèi)部的數(shù)組, 使用for-in loop循環(huán)*/
for (i in myObj.cars) {
x += "<h1>" + myObj.cars[i].name + "</h1>";
for (j in myObj.cars[i].models) {
x += myObj.cars[i].models[j] + "<br>";
}
}
document.getElementById("demo").innerHTML = x;
</script>
</body>
</html>
1. 修改數(shù)組值
使用索引號(hào)修改數(shù)組:
myObj.cars[1] = "Mercedes";完整代碼：<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>項(xiàng)目</title>
</head>
<body>
<p id="demo"></p>
<script>
var myObj, i, x = "";
myObj = {
"name":"John",
"age":30,
"cars":[ "Ford", "BMW", "Fiat" ]
};
myObj.cars[1] = "Mercedes";
for (i in myObj.cars) {
x += myObj.cars[i] + "<br>";
}
document.getElementById("demo").innerHTML = x;
</script>
</body>
</html>
2. 刪除數(shù)組中的項(xiàng)目
使用delete關(guān)鍵字從數(shù)組中刪除:
delete myObj.cars[1];
四、總結(jié)
本文基于JavaScript基礎(chǔ)，講解了JSON數(shù)組中，如何以數(shù)組作為JSON的對(duì)象 ，對(duì)象中如何去嵌套數(shù)組，常見(jiàn)的修改，刪除數(shù)組，都做了詳細(xì)的講解。
希望大家可以根據(jù)文章的內(nèi)容，積極嘗試，有時(shí)候看到別人實(shí)現(xiàn)起來(lái)很簡(jiǎn)單。但是到自己動(dòng)手實(shí)現(xiàn)的時(shí)候，總會(huì)有各種各樣的問(wèn)題，切勿眼高手低，勤動(dòng)手，才可以理解的更加深刻。
代碼很簡(jiǎn)單，希望能夠幫助你。
