How to remove duplicate arrays in an array?

user_14636357 0
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const arr = [[1, 2], [1, 2], [3, 4], [7, 7]];

how to remove duplicate arrays from the given array? The first two elements of the array are the same. I couldn't fix it with the set.

javascript
4 Answers

Use method filter().

const arr = [[1, 2], [1, 2], [3, 4], [7, 7]];
const arrNoDouble = arr.filter((a = {}, b => !(a[b] = b in a)));

console.log(JSON.stringify(arrNoDouble));

user_135734440

The easiest way to do this:

const arr = [
  [1, 2],
  [1, 2],
  [3, 4],
  [7, 7]
];
const newArr = Array.from(new Set(arr.map(JSON.stringify)), JSON.parse)


console.log(newArr)

user_147502160

You could convert the array of arrays into an array of strings with JSON.stringify. This way, the Set's filtering magic can filter the values correctly as they are primitive values.

const arr = [[1, 2], [1, 2], [3, 4], [7, 7]];
let el = arr.map(a => JSON.stringify(a));
let set = new Set(el);
let unique = Array.from(set, JSON.parse);

// one liner
let uniqueArr = Array.from(new Set(arr.map(JSON.stringify)), JSON.parse);
console.log(uniqueArr);

user_113895810

You could use this method to create a new array newarr without duplicates from your current array arr:

const arr = [[1, 2], [1, 2], [3, 4], [7, 7]];
const m = {}
const newarr = []

  for (let i=0; i<arr.length; i++) {
    const v = arr[i];
    if (!m[v]) {
      newarr.push(v);
      m[v]=true;
    }
  }

 console.log(newarr);

user_151134910
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