Sorting in javascript

Question

Here's an example of the array that I want to sort looks like.

    [ { nums: 'http://s3.amazonaws.com/1375304393109.png',
        variant: { name: 'original' } },
      { nums: 'http://s3.amazonaws.com/2315456487896.jpg',
        variant: { name: 'original' } },
      { nums: 'http://s3.amazonaws.com/1375304393109.png',
        variant: { name: 'r256x200', size: '256x200' } },
      { nums: 'http://s3.amazonaws.com/1375304393091.jpg',
        variant: { name: 'r256x200', size: '256x200' } },
      { nums: 'http://s3.amazonaws.com/2315456487896.jpg',
        variant: { name: 'r512x400', size: '512x400' } },
      { nums: 'http://s3.amazonaws.com/1375304393091.jpg',
        variant: { name: 'r512x400', size: '512x400' } } ]

I want to sort the array based on the nums(string) key. The way I want to sort the array is very simple: let the same numbers group next to each other, i.e.

    [ { nums: 'http://s3.amazonaws.com/1375304393109.png',
        variant: { name: 'original' } },
      { nums: 'http://s3.amazonaws.com/1375304393109.png',
        variant: { name: 'r256x200', size: '256x200' } },
      { nums: 'http://s3.amazonaws.com/2315456487896.jpg',
        variant: { name: 'original' } },
      { nums: 'http://s3.amazonaws.com/2315456487896.jpg',
        variant: { name: 'r512x400', size: '512x400' } },
      { nums: 'http://s3.amazonaws.com/1375304393091.jpg',
        variant: { name: 'r256x200', size: '256x200' } },
      { nums: 'http://s3.amazonaws.com/1375304393091.jpg',
        variant: { name: 'r512x400', size: '512x400' } } ]

It doesn't have to be in any order, as long as same numbers group up. What is the fastest way of doing this?

Sorry about the confusion. I guess this is slightly more complicated version of the original question. Anyone has good ideas?

Have you read the 'Related' links in the right column on this Stack Overflow page? I suspect one of them will help. — Lee Meador, Jul 31 '13 at 21:30

phiresky · Accepted Answer · 2013-07-31T22:12:43.163

0

for comparing numbers:

array.sort(function(a,b) { return a.nums - b.nums })

for comparing strings (your case):

 array.sort(function(a,b) { return a.nums.localeCompare(b.nums) })

edited Jul 31 '13 at 22:12

answered Jul 31 '13 at 21:30

phiresky

406
4
15

glad you made that edit. – CBIII Jul 31 '13 at 21:35
2

The function used for sorting has to return a number, in case the return one is a negative value, a is before b. If positive b before a and if it's 0 they're equals as long as that function or order is concerned – mitomed Jul 31 '13 at 21:42
How does this work for strings though? Thanks for the response! – jensiepoo Jul 31 '13 at 21:46
@jensiepoo It works because javascript automatically casts; you could also use parseInt(string) to make sure – phiresky Jul 31 '13 at 21:48
Question updated. I tried the described way, but seems not to work... Thanks for the input! – jensiepoo Jul 31 '13 at 22:03
see, you DO need to use <.. for strings. take that, @thg435 – phiresky Jul 31 '13 at 22:07
But now you are always returning `true` or `false`, (`1` or `0`), never `-1`. Since the OP only wants to group the objects, it might not make a difference, but it's not a correct sort callback. – Felix Kling Jul 31 '13 at 22:08
@jensiepoo answer updated, works again – phiresky Jul 31 '13 at 22:08
@phiresky: no, `>` is still wrong. Please read the manual (link in the comments to the question). – georg Jul 31 '13 at 22:11
@FelixKling okay, updated again just for you – phiresky Jul 31 '13 at 22:11

score 0 · Answer 2 · answered Jul 31 '13 at 21:35

0

You need to map the array of objects into an array of strings, and you need to sort the strings:

array.map(function(o) {return o.nums;}).sort()

That's the closest you can get to the sample output you provided:

["1375304393091", "1375304393091", "1375304393109", "1375304393109", "2315456487896", "2315456487896"]

answered Jul 31 '13 at 21:35

Ray Waldin

3,217
1
16
14

That sorts the property values, but not the objects. (OP seemed to have edited the question) – Felix Kling Jul 31 '13 at 22:09

Sorting in javascript

2 Answers2