Access elements in json object like an array [dupl

问题:

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Closed 7 years ago.

Possible Duplicate:
I have a nested data structure / JSON, how can I access a specific value?

I have a json object, like the one below:

[
  ["Blankaholm", "Gamleby"],
  ["2012-10-23", "2012-10-22"],
  ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har.],
  ["57.586174","16.521841"], ["57.893162","16.406090"]
]

It consists of 4 "property levels" (city, date, description and coordinates).

What I want to do is to be able to access these levels like in an array like this:

var coordinates = jsonObject[4];

This does obvious not work so my question is how can I do it?

Do I need to decode it or something, and if so how?

回答1:

I found a straight forward way of solving this, with the use of JSON.parse.

Let's assume the json below is inside the variable jsontext.

[
  ["Blankaholm", "Gamleby"],
  ["2012-10-23", "2012-10-22"],
  ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har.],
  ["57.586174","16.521841"], ["57.893162","16.406090"]
]

The solution is this:

var parsedData = JSON.parse(jsontext);

Now I can access the elements the following way:

var cities = parsedData[0];

回答2:

The your seems a multi-array, not a JSON object.

If you want access the object like an array, you have to use some sort of key/value, such as:

var JSONObject = {
  "city": ["Blankaholm, "Gamleby"],
  "date": ["2012-10-23", "2012-10-22"],
  "description": ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har.],
  "lat": ["57.586174","16.521841"], 
  "long": ["57.893162","16.406090"]
}

and access it with:

JSONObject.city[0] // => Blankaholm
JSONObject.date[1] // => 2012-10-22

and so on...

or

JSONObject['city'][0] // => Blankaholm
JSONObject['date'][1] // => 2012-10-22

and so on...

or, in last resort, if you don't want change your structure, you can do something like that:

var JSONObject = {
  "data": [
    ["Blankaholm, "Gamleby"],
    ["2012-10-23", "2012-10-22"],
    ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har.],
    ["57.586174","16.521841"], 
    ["57.893162","16.406090"]
  ]
}

JSONObject.data[0][1] // => Gambleby

回答3:

I noticed a couple of syntax errors, but other than that, it should work fine:

var arr = [
  ["Blankaholm", "Gamleby"],
  ["2012-10-23", "2012-10-22"],
  ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har."], //<- syntax error here
  ["57.586174","16.521841"], ["57.893162","16.406090"]
];


console.log(arr[4]);    //["57.893162","16.406090"]
console.log(arr[4][0]); //57.893162

回答4:

var coordinates = [jsonObject[3][0], 
                   jsonObject[3][0],
                   jsonObject[4][1], 
                   jsonObject[4][1]];