How use natural sorting in array of strings?

Question

I have the following array and sort result:

['53-15-9', '53-15-10', '53-15-8'].sort() // => ["53-15-10", "53-15-8", "53-15-9"]

but I need to get the following result:

["53-15-8", "53-15-9", "53-15-10"];

How could I get desired result?

[How to define custom sort function in javascript](http://stackoverflow.com/q/5002848/104380) — vsync, Jan 19 '16 at 18:46
you should check @Maxali's answer. Doesn't say much, but it's exactly what you need. Also - learn how to provide your own comparison function to sort. Check out the [docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort) — Antiokus, Jan 19 '16 at 18:51

Maxali · Accepted Answer · 2016-01-19T19:12:38.723

4

To compare numbers instead of strings, first remove '-'. When you use arithmetic operation, JavaScript first coverts it to numbers.

'53-15-9'.replace(/-/g,'') gives '53159'. You can use closures in sort() to pass compare function that can simply subtract a from b. The following function will sort the array ascending:

    ['53-15-9', '53-15-10', '53-15-8'].sort(function(a,b){
        return a.replace(/-/g,'') - b.replace(/-/g,'')
    })

Update

As mentioned in the comments, '54-1-1' is less than '53-15-9'. We can change '54-1-1' to '54-01-01'. This only works in double digits. We can do it like:

function customSort(myArray) {
    myArray = myArray.map(function(a,b){
        var ar = a.split('-');

        return ar.map(function(arK, arV){return (arK<10)?'0'+arK : arK.toString();}).join('-');;
    })

    return myArray.sort(function(a,b){
        return a.replace(/-/g,'') - b.replace(/-/g,'')
    });  
}

customSort(['54-1-2','53-15-9', '53-15-10', '53-15-8']);
// => ["53-15-08", "53-15-09", "53-15-10", "54-01-02"]

edited Jan 19 '16 at 19:12

answered Jan 19 '16 at 18:47

Maxali

1,934
2
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And without regex: `return a.split('-').join('') - b.split('-').join('')` – vsync Jan 19 '16 at 18:50
4

But if you add `54-1-1` it will be sorted at the beginning, and probably should be at the end. – Oriol Jan 19 '16 at 18:54
@Oriol because its converting to numbers. and 5,411 is smaller than 531,519. \ – Maxali Jan 19 '16 at 18:57
@Maxali I know why. I was only noting this may be undesired. – Oriol Jan 19 '16 at 18:59
@Oriol I updated to achieve this sort. Check the answer. – Maxali Jan 19 '16 at 19:14

score 0 · Answer 2 · answered Jan 19 '16 at 18:48

You can use a custom function for splitting and sorting the parts.

var array = ['53-15-9', '53-15-10', '53-15-8'];
array.sort(function (a, b) {
    var aa = a.split('-'),
        bb = b.split('-'),
        i, r = 0, l = Math.max(aa.length, bb.length);
    for (i = 0; !r && i < l; i++) {
        r = (aa[i] || 0) - (bb[i] || 0);
    }
    return r;
});

document.write('<pre>' + JSON.stringify(array, 0, 4) + '</pre>');

juvian · Answer 3 · 2016-01-19T19:30:05.517

You need to define your own custom sorting function. Here is an example:

['53-15-9', '53-15-10', '53-15-8','2', '53-14-4','53-15-99'].sort(function(a,b){ // a and b are elements of the array
  // split by - and convert values to number 
  a = a.split('-').map(function(val){return Number(val)}) 
  b = b.split('-').map(function(val){return Number(val)})

  // if one has less elements than another, we consider it should go first
  if(a.length != b.length) return a.length > b.length

  //else, one goes after another if one of its elements is greater than the others at that index
  return a.some(function(val, index){
      return val > b[index]
  }) == 0 ? -1 : 1   

})

//output: ["2", "53-14-4", "53-15-8", "53-15-9", "53-15-10", "53-15-99"]

Note you are returning booleans instead of numbers. `false` will be treated as `0`, which means both values should be considered equal. I can't find any counterexample, but I'm not sure this is completely well-defined. If it isn't, the result of the sort will be implementation-dependent. — Oriol, Jan 19 '16 at 19:20

score 0 · Answer 4 · answered Jan 19 '16 at 18:51

['53-15-9', '53-15-10', '53-15-8'].sort(function(a, b) {
  var aNum = parseInt(a.replace(/-/g, ''));
  var bNum = parseInt(b.replace(/-/g, ''));
  return aNum < bNum ? -1 : aNum > bNum ? 1 : 0;
});

Assuming you want to sort them in numerical order including all the sections, simply remove the -, parse them as an int and then sort the ints in a custom sort function.

score 0 · Answer 5 · answered Jan 19 '16 at 18:53

0

var arr = ['53-15-9', '53-15-10', '53-15-8'];
arr.sort(function(a,b){ return a.replace(/-/g,'') - b.replace(/-/g,'') });  
console.log(arr);

output

["53-15-8", "53-15-9", "53-15-10"]

answered Jan 19 '16 at 18:53

Jakir Hossain

2,457
18
23

guest271314 · Answer 6 · 2016-01-19T19:25:03.073

0

Try comparing every number separated by - using Array.prototype.every()

var arr = ["53-15-8", "53-15-9", "53-15-10"];

arr.sort(function(a, b) {
  var curr = a.split(/-/).map(Number);
  var next = b.split(/-/).map(Number);
  return curr.every(function(val, key) {return val <= next[key]}) ? a : b
});

console.log(JSON.stringify(arr))

edited Jan 19 '16 at 19:25

answered Jan 19 '16 at 19:04

guest271314

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`['1', '2']` is sorted as `['2', '1']` – Oriol Jan 19 '16 at 19:07
@Oriol Yes, updating currently. `.every()` not returning expected results. Approach is to compare each number separated by "-" – guest271314 Jan 19 '16 at 19:08
@Oriol See updated post. Adjusted comparison operator to `<=` within `.every()` – guest271314 Jan 19 '16 at 19:11
Now `['1-2', '2-1']` is sorted as `['2-1', '1-2']`. – Oriol Jan 19 '16 at 19:13
@Oriol See updated post. Substituted returning `a` , `b` for `-1`, `1` – guest271314 Jan 19 '16 at 19:27

How use natural sorting in array of strings?

6 Answers6

Update