javascript get unique key values

Question

I have an array which contains the following items:

var jobName = getNextJobName();
var Details = getNextJobDetails();
var item = {
          Name: jobName,
          Details: Details
        };
array.push(item);

I want to extract all the unique names (from the Name field). (in order to create a new object which groups all the details for a specific job).

Could you please show me an efficient way to do this?

'unique names' means what? you need an array or you want individual variables. — Vijay Verma
– Vijay Verma, Commented Oct 4, 2012 at 9:06
Could you show the structure of the object, or the array containing the object(s), are there multiple objects to be compared? As it stands you've only got one name, which is unique by definition. — David Thomas
– David Thomas, Commented Oct 4, 2012 at 9:07
Thanks for your comments, I need an array of all the unique job names. I've edited the code, please tell me if it is clear now. — user429400
– user429400, Commented Oct 4, 2012 at 9:11

Luca Matteis · Accepted Answer · 2012-10-04 09:21:04Z

5

You mean have a list of those objects, and you want to extract all the unique values?

Here's a pretty efficient way, storing the values as keys of a new object called uniq and the value being an array of the 'Details' element.

var arr = [ { Name: 'Alex', Details: 'Foo' }, { Name: 'Igor', Details: 'None' }, { Name: 'Alex', Details: 'Boo' } ];
var uniq = {}; // contains all the unique names
for(var i=0; i<arr.length; i++) {
  var el = arr[i].Name;
  if(!uniq[el]) uniq[el] = []; // start the array
  uniq[el].push(arr[i].Details);
}

http://jsfiddle.net/lmatteis/8LWMH/4/

edited Oct 4, 2012 at 9:21

answered Oct 4, 2012 at 9:12

Luca Matteis

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3 Comments

clentfort Over a year ago

Then after that all you have to do is to iterate over your and check in the uniq object if the key "Name" has a value greater than 1. But be aware: This solution will not work if your names contain characters that are no valid for JSON keys.

Luca Matteis Over a year ago

Right yeah. But his question changed. He wants to group all the 'Details' stuff.

clentfort Over a year ago

Oh, I did not see that. I always love when that happens, specially if all of a sudden all given answers are wrong by miles! Good solution, I'd accept it!

Guffa · Accepted Answer · 2012-10-04 09:11:33Z

2

You can use an object to do the matching efficiently, then read the names from the object into an array:

var unique = {};
for (var i = 0; i < jobs.length; i++) {
    unique[jobs[i].Name] = 1;
}
var uniqueArray = [];
for (n in unique) uniqueArray.push(n);

Demo: http://jsfiddle.net/Guffa/4cH4F/

answered Oct 4, 2012 at 9:11

Guffa

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2 Comments

clentfort Over a year ago

This solution only removes things that have duplicate names, in the resulting array they are unique, but they were not unique before.

Guffa Over a year ago

@clentfort: No, this gets an array of all the unique job names, exactly what the OP asked for.

cmd · Accepted Answer · 2013-12-08 19:21:53Z

1

The following code snippet should do the trick:

var _bzAppUnique = 0; //unique variable to increase at each call
function uniqueID() {
    var d = new Date();
    var u = d.getFullYear() + "," + d.getMonth() + "," + 
            d.getHours() + "," + d.getMinutes() + "," + 
            d.getSeconds() + "," + _bzAppUnique;
    _bzAppUnique++;
    return u.replace(/\,/g, "");
}

edited Dec 8, 2013 at 19:21

cmd

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answered Dec 8, 2013 at 19:00

Hasan Khaled Al-Bzoor

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