Can someone recommend a streamlined JavaScript algorithm for identifying the unique arrays within a collection of arrays?

Question

Can someone recommend a streamlined JavaScript algorithm for identifying the unique arrays within a collection of arrays?

Consider the array below:

let array = [[1, 2], [1, 2], [3, 4], [5, 6], [2, 1]]

I am looking for a way to determine the number of unique arrays in this set. Using the array above as an example, the expected result is 3. How can I achieve this? The code snippet provided below was my attempt, but it doesn't yield the correct output.

let distinct = 0
for (let i = 0; i < array.length; i++) {

  for (let j = i + 1; j < array.length - i; j++) {
    let difference = ingredients[i].filter(x => !array[j].includes(x))
     if (difference.length > 0) {
       distinct += 1;   
     } 
   }
 }

 return distinct;

javascript arrays algorithm

Answer 1

Answer №1

Importance of Order in Sub Items

To preserve the order within sub-items, utilize Array.map() to transform each sub-array into a string, employ String() as recommended by @trincot on this source, generate a Set from the array to eliminate duplicates, and ascertain the size of the Set:

const array = [[1, 2], [1, 2], [3, 4], [5, 6]]

const distinct = new Set(array.map(String))

console.log(distinct.size)

If Order is Irrelevant

If the sequence does not matter, arrange each sub-item, then convert it to a string:

const array = [[2, 1], [1, 2], [3, 4], [5, 6]]

const distinct = new Set(array.map(o => String(o.sort())))

console.log(distinct.size)

Answer 2

Importance of Order in Sub Items

To preserve the order within sub-items, utilize Array.map() to transform each sub-array into a string, employ String() as recommended by @trincot on this source, generate a Set from the array to eliminate duplicates, and ascertain the size of the Set:

const array = [[1, 2], [1, 2], [3, 4], [5, 6]]

const distinct = new Set(array.map(String))

console.log(distinct.size)

If Order is Irrelevant

If the sequence does not matter, arrange each sub-item, then convert it to a string:

const array = [[2, 1], [1, 2], [3, 4], [5, 6]]

const distinct = new Set(array.map(o => String(o.sort())))

console.log(distinct.size)

Answer 3

Answer №2

I just went over your syntax and made the necessary corrections without looking at your algorithm. Have I captured what you intended to write?:

let array = [
  [1, 2],[1, 2],[3, 4],[5, 6]
];

console.log(countDistinctArrays(array));

function countDistinctArrays(parentArray) {
  let distinct = 0;
  for (let i = 0; i < parentArray.length; i++) {
    for (let j = i + 1; j < parentArray.length - i; j++) {
      let difference = parentArray[i].filter(x => !parentArray[j].includes(x))
      if (difference.length > 0) {
        distinct += 1;
      }
    }
  }
  return distinct;
}

Answer 4

I just went over your syntax and made the necessary corrections without looking at your algorithm. Have I captured what you intended to write?:

let array = [
  [1, 2],[1, 2],[3, 4],[5, 6]
];

console.log(countDistinctArrays(array));

function countDistinctArrays(parentArray) {
  let distinct = 0;
  for (let i = 0; i < parentArray.length; i++) {
    for (let j = i + 1; j < parentArray.length - i; j++) {
      let difference = parentArray[i].filter(x => !parentArray[j].includes(x))
      if (difference.length > 0) {
        distinct += 1;
      }
    }
  }
  return distinct;
}

Answer 5

Answer №3

If you attempted this task, here's a different approach. First, convert the inner arrays to strings, remove any duplicates, and then parse the strings back into arrays.

var arr =  [[1, 2], [1, 2] ,[3, 4] ,[5, 6]];
var uniqueArrays = arr.map(ar=>JSON.stringify(ar))
  .filter((item, index, array) => array.indexOf(item) === index)
  .map(str=>JSON.parse(str));

console.log(uniqueArrays.length);

Answer 6

If you attempted this task, here's a different approach. First, convert the inner arrays to strings, remove any duplicates, and then parse the strings back into arrays.

var arr =  [[1, 2], [1, 2] ,[3, 4] ,[5, 6]];
var uniqueArrays = arr.map(ar=>JSON.stringify(ar))
  .filter((item, index, array) => array.indexOf(item) === index)
  .map(str=>JSON.parse(str));

console.log(uniqueArrays.length);

Can someone recommend a streamlined JavaScript algorithm for identifying the unique arrays within a collection of arrays?

Answer №1

Importance of Order in Sub Items

If Order is Irrelevant

Answer №2

Answer №3

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