How can i get the number without repetition?

Question

i want to get the number with only one repitition:

let results = [2, 2, 1, 2, 3, 3, 1]
let pivot = 1
let cont = 0
let unitaries = []
for (var i = 0; i < results.length; i++) {
  if (pivot !== results[i + 1]) {
    pivot = results[i]
    if (cont === 0) {
      unitaries.push(results[i])
      results.splice(i, 1);
    }
    cont++
  }
}
console.log(unitaries)

i want to get [1,2,1], but right now i am getting only [2]

Does this answer your question? [Javascript array sort and unique](https://stackoverflow.com/questions/4833651/javascript-array-sort-and-unique) Just remove Sort — filimonic, Aug 10 '20 at 23:42
@filimonic It shouldn't remove all duplicates. Just consecutive duplicates. Notice that the desired result has `1` twice. — Barmar, Aug 10 '20 at 23:44

filimonic · Answer 1 · 2020-08-11T00:41:32.677

1

Here it is modifying original array.

const results = [2, 2, 1, 2, 3, 3, 1]
for (let i = 0; i < results.length;) 
{
  let j = i;
  while (j < results.length)
  {
    if (results[j] === results[i]) j++;
    else break; 
  }
  if ((j - 1) > i) results.splice(i, j - i);
  else i++;
}
console.log(results);

edited Aug 11 '20 at 00:41

answered Aug 11 '20 at 00:14

filimonic

3,988
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Robo Robok · Accepted Answer · 2020-08-11T00:04:19.737

0

Just overwrite your original array using Array.prototype.filter:

let results = [2, 2, 1, 2, 3, 3, 1];

results = results.filter(
    (n, i, array) => n !== array[i - 1] && n !== array[i + 1]
);

console.log(results); // [1, 2, 1]

edited Aug 11 '20 at 00:04

answered Aug 10 '20 at 23:40

Robo Robok

21,132
17
68
126

but i need to delete that element from origin results array – Aug 10 '20 at 23:43
Does my updated answer help? I just reversed the previous `filter()`. – Robo Robok Aug 10 '20 at 23:45
@RoboRobok I think he means he needs to modify the original array in place. – Barmar Aug 10 '20 at 23:46
@Barmar it shouldn't make any difference in most cases. – Robo Robok Aug 10 '20 at 23:47
@jdode If you're modifying the original array, why do you print the `unitaries` array? – Barmar Aug 10 '20 at 23:47
@jdode After you're done you can do `results.splice(0, results.length, ...unitaries)` to overwrite the original array. – Barmar Aug 10 '20 at 23:50
@Barmar but it's a `let`, so it can be overwritten. – Robo Robok Aug 10 '20 at 23:58

How can i get the number without repetition?

2 Answers2