Question

我有一阵列,如以下一环。

 var my_cars= new Array()
 my_cars["cool"]="Mustang";
 my_cars["family"]="Station Wagon";
 my_cars["big"]="SUV";

I want to convert it using Stringify to json object. I want to know after conversion how the json object will look like.

Also when i have this object How I can convert it back to associative array again.

Answer 1

First of all, by making my_cars an array and stringifying it, you don t get what you expect.

var my_cars= new Array()
my_cars["cool"]="Mustang";
my_cars["family"]="Station Wagon";
my_cars["big"]="SUV";
alert(JSON.stringify(my_cars));

该通知<代码>[。

您希望从<代码>{}开始:

var my_cars= {};
my_cars["cool"]="Mustang";
my_cars["family"]="Station Wagon";
my_cars["big"]="SUV";
alert(JSON.stringify(my_cars));

这一警告

{"cool":"Mustang","family":"Station Wagon","big":"SUV"}

将物体从舱面上回收,使用JSON.parse()。

var s = JSON.stringify(my_cars);
var c = JSON.parse(s);
alert(c.cool);

这一警告 "Mustang".

See http://jsfiddle.net/Y2De9/

Answer 2

No,But 用户想要使用阵列而不是json。

通常的Java 字体阵列旨在拥有数字指数的数据。你可以把钥匙贴上标签(如果你想要储存一个拥有正常、定购、数字指数化数据的阵列的元数据,那么这就是有益的),但这只是它们设计的。 JSON阵列数据类型无法标明阵列上的钥匙。

If you want named keys, use an Object, not an Array.

* <https://stackoverflow.com/a/16196369/4023394>>source

var test = [];           // Object
test[0] =  test ;        //this will be stringified

Now if you want key value pair inside the array

test[1] = {};          // Array
test[1][ b ]= item ;
var json = JSON.stringify(test);

产出

"["test",{"b":"item"}]"

因此,你可以使用一个包含阵列的指数,也可以使用。

var my_cars= [];
my_cars[0]={};
my_cars[0]["cool"]="Mustang";
my_cars[1]={};
my_cars[1]["family"]="Station Wagon";
my_cars[2]={};
my_cars[2]["big"]="SUV";
console.log(JSON.stringify(my_cars));

Output

"[{"cool":"Mustang"},{"family":"Station Wagon"},{"big":"SUV"}]"

Answer 3

把我的意见变成一个答案,以便我能向你们展示一个法典榜样。

这些阵列在 j中没有。您应当把物体用于像这样的非数字钥匙。射线指数应为数字。 Java印物体可对钥匙使用任意价值(如你的例子)。由于Arrays自己是物体,“耳光”会发生,但你不会找到正常的Array方法。例如,研究这一法典的例子。

var my_cars= new Array()
my_cars["cool"]="Mustang";
my_cars["family"]="Station Wagon";
my_cars["big"]="SUV";
alert(my_cars.length);  // alerts 0

You have only added properties to the underlying object, not actually added elements to the Array. You should use an Object for this, not an Array. Javascript does not actually have an Associative Array. It has an Object who s properties can often be used like one would use an Associate Array in other languages. But, it s an Object, not an Array.

Answer 4

"JavaScript does not support arrays with named indexes"

The most close state to an associative array is an array with entries converted to properties (as in your case), so I provide a solution for this exact case.

幸运的是, Chrome星公司认为它是一种关联阵列:["cool”:“Mustang”、“家庭”:“Station Wagon”、“big”:“SUV”](Check with )

NOTE: open browser s console before running the snippet

var my_cars= new Array()
my_cars["cool"]="Mustang";
my_cars["family"]="Station Wagon";
my_cars["big"]="SUV";


let toAssociative=(keys, values)=> 
    values.reduce((acc, cv)=>{
       acc[acc.shift()]=cv
       return acc;
    }, keys)    


let fromAssociative = (assArr)=>({...assArr})

let serialized = JSON.stringify(fromAssociative(my_cars))

let o = JSON.parse(serialized)

let restored = toAssociative(Object.keys(o) , Object.values(o))

//NOTE: Look at the browser s console before executing (not SO console)

console.log("orig:",my_cars) 
//[cool: "Mustang", family: "Station Wagon", big: "SUV"]

console.log("serialized:",serialized)
//{"cool":"Mustang","family":"Station Wagon","big":"SUV"}
 
console.log("restored:",restored) //NOTE: look at the browser s console (F12)
//[cool: "Mustang", family: "Station Wagon", big: "SUV"]

Answer 5

If for some reason you cannot convert your array into object, for instance you are working on a big framework or legacy code that you dont want to touch and your job is only to add som feature which requires JSON API use, you should consider using JSON.stringify(json,function(k,v){}) version of the API. In the function you can now decide what to do with value of key is of a specific type.

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