How can I sort 2D array with JavaScript?

Question

I have any array like this:

arr = [["123", "2017-07-11 15:00", '1'],
      ["124","2017-07-04 16:00", '1'],
      ["125","2017-07-05 12:00", '1'],
      ["126","2017-07-04 21:00", '1'],
      ["127","2017-07-03 02:00", '1'],
      ["128","2017-07-05 11:00", '1'],
      ["129","2017-07-05 14:00", '1']]

And I want to sort by the second element (arr[1]) How Can I do that?

I tired this before:

let b = arr.map(x=> x[1]).sort();
console.log(b);

And this is my console result:

["2017-07-03 02:00", 
"2017-07-04 16:00", 
"2017-07-04 21:00", 
"2017-07-05 11:00", 
"2017-07-05 12:00", 
"2017-07-05 14:00", 
"2017-07-11 15:00"]

But this is my expected result:

[["127", "2017-07-03 02:00", '1'], 
["124","2017-07-04 16:00", '1'], 
["126","2017-07-04 21:00", '1'], 
["128","2017-07-05 11:00", '1'], 
["125","2017-07-05 12:00", '1'], 
["129","2017-07-05 14:00", '1'], 
["123","2017-07-11 15:00", '1']

You need to sort on the *original* array, and access the second item of the sub-arrays inside the sort function. — CertainPerformance, Jul 04 '18 at 08:10
Probably a more appropriate duplicate since it handles date sorting, not string sorting... https://stackoverflow.com/questions/10123953/sort-javascript-object-array-by-date — Reinstate Monica Cellio, Jul 04 '18 at 08:22

Taki · Answer 1 · 2018-07-04T08:17:15.623

0

since arr[1] is a date you need to compare them using new Date() like :

const arr = [
  ["123", "2017-07-11 15:00", '1'],
  ["124", "2017-07-04 16:00", '1'],
  ["125", "2017-07-05 12:00", '1'],
  ["126", "2017-07-04 21:00", '1'],
  ["127", "2017-07-03 02:00", '1'],
  ["128", "2017-07-05 11:00", '1'],
  ["129", "2017-07-05 14:00", '1']
]

const result = arr.sort((a, b) => {
  return new Date(a[1]) - new Date(b[1])
})

console.log(result)

edited Jul 04 '18 at 08:17

answered Jul 04 '18 at 08:12

Taki

15,354
3
20
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Sort functions should not return true or false. – Reinstate Monica Cellio Jul 04 '18 at 08:13
1

@Archer thx for the hint , i just updated the answer – Taki Jul 04 '18 at 08:18
What if it's not a date? – Lynn Jul 04 '18 at 08:30
@Lynn if it's not, you can do `return a[0] - b[0]` or check [these answers](https://stackoverflow.com/questions/1129216/sort-array-of-objects-by-string-property-value-in-javascript) – Taki Jul 04 '18 at 08:34
1

Got it! Thank you so much!!! – Lynn Jul 05 '18 at 03:13

score 0 · Accepted Answer · answered Jul 04 '18 at 08:15

0

See Array.prototype.sort() for more info.

// Input.
const input = [["123", "2017-07-11 15:00", '1'],["124","2017-07-04 16:00", '1'],["125","2017-07-05 12:00", '1'],["126","2017-07-04 21:00", '1'],["127","2017-07-03 02:00", '1'],["128","2017-07-05 11:00", '1'],["129","2017-07-05 14:00", '1']]

// Sort.
const sort = x => x.sort((A, B) => {
  const dateA = new Date(A[1])
  const dateB = new Date(B[1])
  return dateA - dateB
})

// Output.
const output = sort(input)

// Proof.
console.log(output)

answered Jul 04 '18 at 08:15

Arman Charan

4,717
2
18
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If it's not a date formate, how can I sort my array? – Lynn Jul 04 '18 at 08:32
`Array.prototype.sort()` expects a `number`. So for `numbers`: the same strategy applies. For `strings`: `numbers` must be passed manually based on `> / < / ==` comparison. There are examples of each in the documentation I linked @Lynn – Arman Charan Jul 04 '18 at 08:40

How can I sort 2D array with JavaScript?

2 Answers2