How to sort object by key through JSON file parsing in D3.js

Question

I have a JSON file (myfile.json) that looks like this:

{"3":["c","d"], "3.5":["j","k"], "1.5":["a","b"], "2.5":["x","y"] }

What I want to do open the file and sort it using d3.js file opening.

 d3.json('myfile.json',function(err,datafull){
    for (var myval in datafull) {
        console.log(myval);
    }
  });

Now if I do that, the console.log will print they key in unsorted manner. How can I sort the file?

This is different question, because it involves file parsing.

Put each item into an array and then sort the array. Or use `Object.keys()` to get an array of the keys, sort *that* array, then use it to access the properties of the original object in sorted order. But you can't sort a (non-array) object. — nnnnnn, Sep 16 '15 at 00:29

sjm · Accepted Answer · 2015-09-16T01:06:22.423

2

To sort object keys you can use Object.keys() method which gives an array of the given objects keys then you can use the array sort() method.

d3.json('myfile.json',function(err,data){
  keys = Object.keys(data),
  i, len = keys.length;
  keys.sort(function(a, b) {
    return a - b;
  });

  for (i = 0; i < len; i++)
  {
    var a = keys[i];
    console.log(a + ':' + data[a]);
  }
}

See http://jsfiddle.net/sjmcpherso/mvrWb/234/

edited Sep 16 '15 at 01:06

answered Sep 16 '15 at 00:33

sjm

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how do you store `myfile.json` to `myObj`? – neversaint Sep 16 '15 at 00:35
Your output is already appears to be an object, is that not the case? – sjm Sep 16 '15 at 00:37
I need to start from input JSON file. – neversaint Sep 16 '15 at 00:38
neversaint - The `datafull` variable in the code in the question appears to already be an object, so where this answer has `myObj` you'd just substitute `datafull`. – nnnnnn Sep 16 '15 at 00:39
1

@sjm - note that `.sort()` with no comparator callback will do a lexical sort, and I suspect the OP wants a numeric sort. – nnnnnn Sep 16 '15 at 00:41
@nnnnnn thats true, I've added function expression to compare numbers, otherwise it would sort values like: 1.5, 10.5, 3, 3.5 – sjm Sep 16 '15 at 00:48
@sjm: in your example script. Can you put the file name as part of the whole code? – neversaint Sep 16 '15 at 00:55
1

I've updated my answer but that all depends if 'data' is actually an object which I'm guessing it is – sjm Sep 16 '15 at 01:07

How to sort object by key through JSON file parsing in D3.js

1 Answers1