Js searching object with a key

Question

I have a json string which is resulted by an ajax call which looks like this

[ { 
"name":"sourabh", 
"userid":"soruabhbajaj", 
"id":"11", 
"has_profile_image":"0" }, 
{
"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"12", 
"has_profile_image":"0" 
}]

The page on my web app uses "id" value as the identification of an object. So I want to display the name of the user where ever users' name is required. What is the fastest way of getting the right user object to output the name or other values of user using the id value. Thanks in advance.

possible duplicate of Searching for an Object inside the JSON — user113716
– user113716, Commented Sep 23, 2011 at 14:42
Fishy... the question and every answer has received a downvote. — Greg
– Greg, Commented Sep 23, 2011 at 14:53
Please note that this question is about searching inside an array, while "Searching for an Object inside the JSON" is about searching inside an object. — Greg
– Greg, Commented Sep 23, 2011 at 14:58

Joseph Marikle · Accepted Answer · 2011-09-23 15:21:39Z

1

Ok... this answer provides for a lot of overhead at the start, but then makes it faster to reference by id later. It basically makes an array that has each item at the same index of its id. Like I said, a lot of overhead at first but little for later processing

var data = [{"name":"sourabh", 
"userid":"soruabhbajaj", 
"id":"11", 
"has_profile_image":"0" }, 
{"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"12", 
"has_profile_image":"0" }, 
{"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"27", 
"has_profile_image":"0" }, 
{"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"3", 
"has_profile_image":"0" }, 
{"name":"myname", 
"userid":"myuserid", 
"id":"5", 
"has_profile_image":"0" }, 
{"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"2", 
"has_profile_image":"0" }]

arr = [];

data.sort(function(a,b){return Number(a.id) - Number(b.id);})

var k = 0;
var offset = Number(data[0].id);
for(var i = offset; i <= Number(data[data.length - 1].id);i++)
  if(Number(data[k].id) === i)
    arr.push(data[k++]);
  else
    arr.push({})

//now you can reference like so:
alert(arr[5 - offset].name) // alerts "myname"

edited Sep 23, 2011 at 15:21

answered Sep 23, 2011 at 15:01

Joseph Marikle

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3 Comments

Sourabh Over a year ago

Yeah, This can be the answer i was waiting for. I think I am satisfied with your answer. Thanks dude, A +1 + acceptance.. :)

Greg Over a year ago

Be cautious, depending on the range of the user ids this method could create an enormous array and a huge number of empty objects. For example, if user ids start at 5000, the array will be at least 5000 elements large and at least 5000 objects will be created.

Joseph Marikle Over a year ago

@Greg good point. I've updated my answer to help that a little at least.

Mircea Soaica · Accepted Answer · 2011-09-23 14:42:38Z

0

Make the result from ajax call like this:

{ "11": { 
"name":"sourabh", 
"userid":"soruabhbajaj", 
"id":"11", 
"has_profile_image":"0" }, 
"12": {
"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"12", 
"has_profile_image":"0" 
}}

this way you can use it from javascript like this:

userName = jsonResponse[id].name

answered Sep 23, 2011 at 14:42

Mircea Soaica

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1 Comment

Sourabh Over a year ago

I was thinking about this method but this increases overhead on my controller of formatting the data in this format.

Joseph Marikle · Accepted Answer · 2011-09-23 14:45:32Z

0

var data = [{"name":"sourabh", 
"userid":"soruabhbajaj", 
"id":"11", 
"has_profile_image":"0" }, 
{"name":"sourabh", 
"userid":"sourabhbajaj", 
"id":"12", 
"has_profile_image":"0" }]

for(var i in data)
  if(data[i]["id"] == 11)
    alert(data[i].name);

It's very simple :)

answered Sep 23, 2011 at 14:45

Joseph Marikle

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2 Comments

Sourabh Over a year ago

Its simple but using a loop will slow down my app. I am looking for a more efficient way of doing this.

Joseph Marikle Over a year ago

@Sourabh are the id's contiguous (1,2,3,4...12) without any breaks in between? (and are they in numerical order)

Greg · Accepted Answer · 2011-09-23 15:06:07Z

0

Either search the array each time

function getUser(users, id) {
  var user = null;
  $.each(users, function() {
    if (this.id === id) {
      user = this;
      return false; // break out of loop
    }
  });
  return user
}

or create a reusable lookup table (assumes unique user ids):

function toLookup(users) {
  var lookup = {};
  $.each(users, function() {
    lookup[this.id] = this;
  });
  return lookup;
}

function getUser(lookup, id) {
  return lookup[id] || null;
}

edited Sep 23, 2011 at 15:06

answered Sep 23, 2011 at 14:43

Greg

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1 Comment

Greg Over a year ago

I had a couple bugs in the first version - fixed now.

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