遍历JSON嵌套数组

Question

With this JSON object:

{
  "date_price": [
    {
      "date": "Jan 2000",
      "price": 1394.46
    },
    {
      "date": "Feb 2000",
      "price": 1366.42
    },
    {
      "date": "Mar 2000",
      "price": 1498.58
    },
    {
      "date": "Apr 2000",
      "price": 1452.43
    }
  ]
}

How can I loop through it and save each pair date-price in a simple array, using something like this, for example:

var transformation = [];

transformation.push({date: i, price: d})

Because the problem here is that in the console, when I print the JSON object, it says they are objects inside of the array, so I can't use the forEach() loop

Answer 1

Assuming you've parsed the JSON to an object...

var obj = JSON.parse(json);

... map over the data.

Note: instead of an array of objects (as you ask for in your question) based on your response to my question you want a nested array structure instead.

ES5

var transformation = obj.date_price.map(function(el) {
  return [ el.date, el.price ];
});

ES6

var transformation = obj.date_price.map(el => [ el.date, el.price ]);

OUTPUT

[
  ["Jan 2000", 1394.46],
  ["Feb 2000", 1366.42],
  ["Mar 2000", 1498.58],
  ["Apr 2000", 1452.43]
]

DEMO

Answer 2

EDIT: as you already have the JSON as an object, then you merely need to get the date_price property from it. That's an array of exactly the object types you require... so...

var result = jsonObject.date_price; // THIS is your array here.

Or...

var result = jsonObject['date_price']; // THIS is your array here.

---

Previous answer given, which assumes a JSON string...

Simply using this...

// This is just your JSON string above.
var text = '{ "date_price": [ { "date": "Jan 2000", "price": 1394.46 }, { "date": "Feb 2000", "price": 1366.42 }, { "date": "Mar 2000", "price": 1498.58 }, { "date": "Apr 2000", "price": 1452.43 } ] }';

// Parse it as an object.
var obj = JSON.parse(text);

// Get the date_price property, which is an array already.
var result = obj.date_price;

// Some output here, to illustrate...
console.log(result);
for (var i = 0; i < result.length; i++) {
    console.log(result[i]);
}

Answer 3

Simple solution using JSON.parse and Array.map functions:

 var jsonStr = '{"date_price": [{ "date": "Jan 2000", "price": 1394.46 },{"date": "Feb 2000", "price": 1366.42},{"date": "Mar 2000","price": 1498.58},{"date": "Apr 2000","price": 1452.43}]}', jsonObj = JSON.parse(jsonStr); //var transformation = jsonObj["date_price"]; // to get a nested array var transformation = jsonObj["date_price"].map(function(v){ return v; }); // to perform test artificial loop document.write("<pre>"+ JSON.stringify(transformation, 0, 4) + "</pre>"); 

Answer 4

You can do something like this:

var abc = {
 "date_price": [
{
  "date": "Jan 2000",
  "price": 1394.46
},
{
  "date": "Feb 2000",
  "price": 1366.42
},
{
  "date": "Mar 2000",
  "price": 1498.58
},
{
  "date": "Apr 2000",
  "price": 1452.43
}
]
}
var array = $.map(abc, function(value, index) {
    return [value];
});

https://jsfiddle.net/atg5m6ym/3271/

Answer 5

The simplest solution. It's already in the format you need. You just need to remove the nesting.

var obj = {
  "date_price": [
    {
      "date": "Jan 2000",
      "price": 1394.46
    },
    {
      "date": "Feb 2000",
      "price": 1366.42
    },
    {
      "date": "Mar 2000",
      "price": 1498.58
    },
    {
      "date": "Apr 2000",
      "price": 1452.43
    }
  ]
};

var array = obj['date_price'];

And that's it.