javascript - JSON count an Array elements and wrap in - Stack Overflow

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Well I've just discovered JSON today but I have a problem using it correctly. I really can't find a solution...

Basically, I just want to count the elements of my array (count all the dM), and wrap on a specific element (dM1 for example).

Here is my code so that you can understand: /

Well I've just discovered JSON today but I have a problem using it correctly. I really can't find a solution...

Basically, I just want to count the elements of my array (count all the dM), and wrap on a specific element (dM1 for example).

Here is my code so that you can understand: http://jsfiddle/dRycS/9/

• javascript
• jquery
• json

Share Follow edited Mar 16, 2011 at 15:35 Jakub Hampl 40.6k1010 gold badges7979 silver badges111111 bronze badges asked Mar 16, 2011 at 15:30 SindarSindar 10.9k77 gold badges3434 silver badges4545 bronze badges

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4 Answers 4

Sorted by: Reset to default 3

Adding to what @Pointy said here is your code modified: JSFiddle Demo

Object.size = function(obj) {
    var size = 0, key;
    for (key in obj) {
        if (obj.hasOwnProperty(key)) size++;
    }
    return size;
};

var dMContent = {
    "dM1" : [
        {
            "name" : "EeEeEeEe",
            "link" : "http://test."
        },
        {
            "name" : "FfFfFfFf",
            "link" : "http://test."
        },
        {
            "name" : "GgGgGgGg",
            "link" : "http://test."
        } 
    ],
    "dM2" : [
        {
            "name" : "EeEeEeEe",
            "link" : "http://test."
        },
        {
            "name" : "FfFfFfFf",
            "link" : "http://test."
        } 
    ],
    "dM3" : [
        {
            "name" : "EeEeEeEe",
            "link" : "http://test."
        } 
    ] 
};

var STORAGE = JSON.stringify(dMContent);
var parsed = JSON.parse(STORAGE);


// WHAT I WANT TO DO

// Count the number of dM
console.log(Object.size(parsed));  //gives you 3

//display the content
for(var i in parsed){
    console.log('data in ' + i);
    for(var j=0; j<parsed[i].length; j++){
         console.log(parsed[i][j].name + ' ' + parsed[i][j].link);
    }
}

What you've got there is not an Array; it's an Object. Array objects do have a "length" property, but Objects do not.

It's not clear exactly what you want; if you wanted to count every property of every object inside of "dMContent", you'd write something to count recursively. For a single "layer" of an object, something like this might be what you want:

function objectSize(obj) {
  var count = 0;
  for (var k in obj) {
    if (obj.hasOwnProperty(k)) ++count;
  }
  return count;
}

In your code dMContent is an Object, not an Array.

To count elements in an Object, do this:

var i = 0;
for (x in parsed) {
    if (parsed.hasOwnProperty(x)) {
        i++;
    }
}
alert(i);

Try this: function objectCount(obj) {

objectcount = 0;
$.each(obj, function(index, item) {
    objectcount = objectcount + item.length;
});
return objectcount;
}

objectCount(obj); where obj is a json object with json array as sub objects

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