如何访问所有嵌套的关联数组元素？

Question

Situation : I receive JSON array from jQuery <-> PHP Ajax request. Here's structure of unparsed JSON aray :

{"Focus":{"id":2,"brand":"Ford","name":"Focus"}}

And after using JSON.parse(json); the structure looks like :

    Focus: Object
       brand: "Ford"
       id: 2
       name: "Focus"

Problem : I want to access all array's '1st tier' elements and use them like an object, but none of the following ways works :

for (var entity in dataTable)
{
   formattedText += entity['brand'] + " " + entity['name'] + "<br>";
   OR
   formattedText += entity.brand + " " + entity.name + "<br>";
   OR
   formattedText += dataTable[0]['brand'] + " " + dataTable[0]['name'] + "<br>";
}

Any solutions how to read values of all object in this array?

Answer 1

The for..in loop uses keys and does not return the elements themself: for (var key in dataTable)
You would then access each element with dataTable[key] . The key is actually the name of the Element.

You where using it as you would use a for..of loop, but that is a new feature not supported in all Browsers yet.

Demo:

 var dataTable = {"Focus":{"id":2,"brand":"Ford","name":"Focus"}} var formattedText = "" for (var key in dataTable) { formattedText += dataTable[key]['brand'] + " " + dataTable[key]['name'] + "<br>"; } document.write(formattedText) 

Answer 2

Object.keys will return array of all the keys of the object

You can loop( forEach / for-loop ) through the keys to get the expected output.

Using forEach :

 var dataTable = { "Focus": { "id": 2, "brand": "Ford", "name": "Focus" } } var keys = Object.keys(dataTable); var str = ''; keys.forEach(function(item) { str += dataTable[item].brand + " " + dataTable[item].name; }); alert(str); 

Using for-loop :

 var dataTable = { "Focus": { "id": 2, "brand": "Ford", "name": "Focus" } } var keys = Object.keys(dataTable); var str = ''; for (var i = 0, len = keys.length; i < len; i++) { str += dataTable[keys[i]].brand + " " + dataTable[keys[i]].name; } alert(str); 

Answer 3

The correct syntax to write this would be:

When you loop, you'll get the key name in the variable entity and then use that to get the value, also, you need to access the associative array inside the first key ie Focus

var dataTable = JSON.parse('{"Focus":{"id":2,"brand":"Ford","name":"Focus"}}');
var formattedText = '';
for (var entity in dataTable.Focus) {
    formattedText += dataTable.Focus['brand'] + " " + dataTable.Focus['name'] + "<br>";
}

Answer 4

Sounds like you're using each function in a wrong way. in your each function change arguments to key and value like this:

$.each(dataTable, function (key, value) {
     //access key and values here
});

In your case u should iterate again over key and values of your key values.