How to remove nested attributes?

Question

I have this JSON file: http://danish-regional-data.googlecode.com/svn/trunk/danish_regional_data.json

How do I remove all the attribues within_5_km, within_10_km, within_25_km, within_50_km, within_100_km for all postcodes?

I have read this question: Remove a JSON attribute

$(document).ready(function() {

    $.getJSON("post.json", function(data) {

    var pc = data.postalcodes;
    for (var id in pc) {
       if(pc.hasOwnProperty(id)) {
          for(var attr in pc[id]) {
             if(pc[id].hasOwnProperty(attr) && attr.indexOf('within_') === 0) {
               delete pc[id][attr];
             }
          }
       }
    }

    $("#json").html(pc);

    });

});

Well, you need to recursively loop over your JSON object, searching for those attributes, and delete them if/when they're found, per the answer in your linked question. — Matthemattics, Nov 05 '12 at 14:42
If you're looking to do this after a JSON call to get the data it would be redundant as you'd have had to download them all first to remove them. — Rory McCrossan, Nov 05 '12 at 14:45
@Lübnah - Can you show how to do that? Because in the linked question there is no loop or search :/ — Rails beginner, Nov 05 '12 at 14:45
@Lübnah, actually there is no such thing as JSON object. JSON is used as a representation of an object of specified type. — jwaliszko, Nov 05 '12 at 14:46
@JaroslawWaliszko Okay, that's a bit pedantic, but yes that's technically correct. JSON == JavaScript Object Notation. So, what I /meant/ was the object the OP has expressed in JSON. Happy now? — Matthemattics, Nov 05 '12 at 14:47

Alex Gulakov · Answer 1 · 2016-04-30T02:13:57.573

3

In ES2016 you can use destructing to pick the fields you want for the subset object.

//ES6 subset of an object by specific fields
var object_private = {name: "alex", age: 25, password: 123};
var {name,age} = object_private, object_public = {name,age}


//method 2 using literals
let object_public = (({name,age})=>({name,age}))(object_private);


//use map if array of objects
    users_array.map(u=>u.id)

edited Apr 30 '16 at 02:13

answered Apr 29 '16 at 20:29

Alex Gulakov

87
1
5

Dropping a chunk of code isn't usually very helpful. Can you explain *why* this should work? – Mike Cluck Apr 29 '16 at 22:24

prodigitalson · Accepted Answer · 2012-11-05T15:12:37.657

2

Go to the json url you provided and open the Firebug console. Then drop in the folloing code and execute it:

var p = document.getElementsByTagName('pre');
for(i=0; i < p.length; i++) {

  var data = JSON.parse(p[i].innerHTML);
  var pc = data.postalcodes;

  // this is the code i gave you... the previous is jsut to pull it out of the page
  // in Firebug - this works for me

  for (var id in pc) {
     if(pc.hasOwnProperty(id)) {
        for(var attr in pc[id]) {
          if(pc[id].hasOwnProperty(attr) && attr.indexOf('within_') === 0) {
             console.log('Deleting postalcodes.'+id+'.'+attr);
             delete pc[id][attr];
           }
        }
     }
  }
}

// assume data is the complete json

var pc = data.postalcodes;
for (var id in pc) {
   if(pc.hasOwnProperty(id)) {
      for(var attr in pc[id]) {
         if(pc[id].hasOwnProperty(attr) && attr.indexOf('within_') === 0) {
           delete pc[id][attr];
         }
      }
   }
}

edited Nov 05 '12 at 15:12

answered Nov 05 '12 at 14:51

prodigitalson

60,050
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Of course, this would be after OP converted the JSON string into an actual object – Matthemattics Nov 05 '12 at 14:53
I have tried your solution, but it does not work. I have updated my question with my code. – Rails beginner Nov 05 '12 at 14:58
Absolutely no need for `hasOwnProperty` – Bergi Nov 05 '12 at 15:10
@Lübnah: Well i assumed he was already fine with the parsing. The question didnt ask how to convert a json string to a js object it was about nested iteration. – prodigitalson Nov 05 '12 at 15:14
@Railsbeginner: Try `$("#json").text(JSON.stringify(data));` instead – Bergi Nov 05 '12 at 15:14
@Rails beginner: Did you get any errors? See my update for a test. – prodigitalson Nov 05 '12 at 15:14
@Bergi: True... force of habit (re: hasOwnProperty). – prodigitalson Nov 05 '12 at 15:16
@prodigitalson - I see it deletes in the console, how do I copy/get the new code? – Rails beginner Nov 05 '12 at 15:26
@Railsbeginner, when you delete those attributes in your loop you are augmenting the single copy of you **data** object. Within the loop you are simply creating references to parts of the **data** object. After the loop you can access the new version by referencing the same **data** object – cbayram Nov 05 '12 at 15:30
@cbayram - I see console.dir(data); and then I can just copy the data in the console :) – Rails beginner Nov 05 '12 at 15:44

score 1 · Answer 3 · answered Nov 05 '12 at 15:32

JSON truncated:

var data = {"postalcodes":
{"800":{"id":"800","name":"H\u00f8je Taastrup","region_ids":["1084"],"region_names":["Hovedstaden"],"commune_ids":["169"],"commune_names":["H\u00f8je-Taastrup"],"lat":"55.66713","lng":"12.27888", "within_5_km":["800","2620","2630","2633"],"within_10_km":["800","2600","2605","2620"]},
"900":{"id":"900","name":"K\u00f8benhavn C","region_ids":["1084"],"region_names":["Hovedstaden"],"commune_ids":["101"],"commune_names":["K\u00f8benhavns"],"lat":"55.68258093401054","lng":"12.603657245635986","within_5_km":["900","999"]},
"1417":{"commune_id":"390","region_id":"1085"}}};
var pc = data.postalcodes;
for (var id in pc) {
    var entry = pc[id];
    for(var attr in entry) {
        if(attr.indexOf('within_') === 0) {
            delete entry[attr];
        }
    }
}
console.dir(data); // your data object has been augmented at this point

you can also use regular expression

var data = {"postalcodes":
{"800":{"id":"800","name":"H\u00f8je Taastrup","region_ids":["1084"],"region_names":["Hovedstaden"],"commune_ids":["169"],"commune_names":["H\u00f8je-Taastrup"],"lat":"55.66713","lng":"12.27888", "within_5_km":["800","2620","2630","2633"],"within_10_km":["800","2600","2605","2620"]},
"900":{"id":"900","name":"K\u00f8benhavn C","region_ids":["1084"],"region_names":["Hovedstaden"],"commune_ids":["101"],"commune_names":["K\u00f8benhavns"],"lat":"55.68258093401054","lng":"12.603657245635986","within_5_km":["900","999"]},
"1417":{"commune_id":"390","region_id":"1085"}}};
var regexp = new RegExp("^within_", "i");   // case insensitive regex matching strings starting with within_
var pc = data.postalcodes;
for (var id in pc) {
    var entry = pc[id];
    for(var attr in entry) {
        if(regexp.test(attr)) {
            delete entry[attr];
        }
    }
}
console.dir(data);

score 1 · Answer 4 · answered Jan 05 '17 at 10:58

I have written an npm module unset which exactly does this. You specify json paths similar to the json-path module until the leaf attribute that you want to remove.

let unset = require('unset');
let object = {a: { b: [ {x: 1}, {x: [{ e: 2} ]}]}};
let newObject = unset(object, ['/a/b[*]/x']);

Multiple paths are supported in the second argument

AMember · Answer 5 · 2012-11-05T15:47:43.417

0

well you can do this:

var postalcodes = YOUR JSON;

for(var code in postalcodes)
{
 delete postalcodes[code].within_5_km;
 .
 .
 .
}

you will probably want to check if the code contains your properties...

edited Nov 05 '12 at 15:47

answered Nov 05 '12 at 14:44

AMember

3,037
2
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How to remove nested attributes?

5 Answers5

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