HI,

I'm having a JSON parsed return object set.

{
  "word":[
      "offered",
      "postings"
  ],

  "annotation":[
      ["offered highlighted","this is also given as annotation","This annotation has been added here currently","offering new annotation points","\"offered\" is in the sense of languages"],
      ["my postings","this is new annotation for postings.","my postings","this is posting annotation.... Working for the feature of the annotation."]
  ],

  "user":[
  ["","","vinoth","Anonymous","Vinoth"],
  ["Anonymous","vinoth","Anonymous","Arputharaj"]
  ],

  "id":[
  ["58","60","61","63","68"],
  ["32","57","59","62"]
  ],

  "ment":
  {
    "id58":["first ment","This is a old ment for this annotation","Next level of menting.","Fourth ment to this annotation","testing"],
    "id61":["this is an old annotation.\r\nMy ment is very bad about this.","Second ment to this annotation"],
    "id57":["I want to add one more ment to this"]
    },

    "mentUser":{
      "id58":["vinoth","Anonymous","Vinothkumar","Vinothkumar","vinoth"],
      "id61":["Anonymous","Commentor"],
      "id57":["vinoth"]
      }
  }

I want to know about the length of each object and array.

I've used .length to get the length of annotation[0].length. I'm getting the expected result i.e.: 5. The same is to "user" & "id".

But I'm not getting the lengths of "word", "id58", "id61", etc... Also I want to know about the length of the ment & mentUser.

Please help me in this.

HI,

I'm having a JSON parsed return object set.

{
  "word":[
      "offered",
      "postings"
  ],

  "annotation":[
      ["offered highlighted","this is also given as annotation","This annotation has been added here currently","offering new annotation points","\"offered\" is in the sense of languages"],
      ["my postings","this is new annotation for postings.","my postings","this is posting annotation.... Working for the feature of the annotation."]
  ],

  "user":[
  ["","","vinoth","Anonymous","Vinoth"],
  ["Anonymous","vinoth","Anonymous","Arputharaj"]
  ],

  "id":[
  ["58","60","61","63","68"],
  ["32","57","59","62"]
  ],

  "ment":
  {
    "id58":["first ment","This is a old ment for this annotation","Next level of menting.","Fourth ment to this annotation","testing"],
    "id61":["this is an old annotation.\r\nMy ment is very bad about this.","Second ment to this annotation"],
    "id57":["I want to add one more ment to this"]
    },

    "mentUser":{
      "id58":["vinoth","Anonymous","Vinothkumar","Vinothkumar","vinoth"],
      "id61":["Anonymous","Commentor"],
      "id57":["vinoth"]
      }
  }

I want to know about the length of each object and array.

I've used .length to get the length of annotation[0].length. I'm getting the expected result i.e.: 5. The same is to "user" & "id".

But I'm not getting the lengths of "word", "id58", "id61", etc... Also I want to know about the length of the ment & mentUser.

Please help me in this.

• javascript
• json

2 Answers 2

To count the number of properties an object has, you need to loop through the properties but remember to use the hasOwnProperty function:

var count = 0;
for (var p in obj) {
    if (obj.hasOwnProperty(p)) {
        count++;
    }
}

If you forget to do that, you will be looping through inherited properties. If you (or some library) has assigned a function to the prototype of Object, then all objects will seem to have that property, and thus will seem one item "longer" than they intrinsically are.

To avoid the need to remember this, consider using jQuery's each instead:

var count = 0;
$.each(obj, function(k, v) { count++; });

UPDATE With current browsers:

Object.keys(someObj).length

The value for the key word in your example (let's call it obj) is an array, so obj.word.length should be 2.

The value for ment and mentUser is an object, which does not have length per se, so you'll need to count them yourself:

var length=0;
for(var dummy in obj.ment) length++;