Need to find or count duplicates in multidimensional array

Question

I need to count the no of duplicates in an multidimensional array and give alert if duplicates found.

Arr =[[2,"sk"],[3,"df"],[7,"uz"],[3,"df"],[7,"gh"]]

Suggestions: Count can be done in this manner that if arr[0] position is equals to next coming positions then it must give a count & needs to check both values combination same. And then for arr[1] position to check for next coming positions and so on for other position till last

Only counts the exact combination Like [3,"df"] at second position equal to [3,"df"] at fourth combination

Expected Output Count :1 Alert duplicate data found

What would the count be for [[2,"sk"],[2,"sk"],[3,"df"],[3,"df"],[3,"df"]]? — Ben Stephens
– Ben Stephens, Commented Jun 13, 2021 at 5:04

Ben Stephens · Accepted Answer · 2021-06-13 05:39:22Z

0

My answer from the original question (except that I've got three items like [3, "df"] in the input array) is:

const input = [
  [2, "sk"], [3, "df"], [7, "uz"], [3, "df"], [7, "gh"],
  [5, "df"], [21, "sk"], [2, "1sk"], [3, "df"]
];

const duplicate_count = input.length - new Set( input.map(JSON.stringify) ).size;

console.log(duplicate_count);

If the count for [[3,"df"],[3,"df"],[3,"df"]] should be one instead of two then perhaps something like:

const input = [
  [2, "sk"], [3, "df"], [7, "uz"], [3, "df"], [7, "gh"],
  [5, "df"], [21, "sk"], [2, "1sk"], [3, "df"]
];

const duplicate_count = [
  ...input
    .map(JSON.stringify)
    .reduce( (acc, v) => acc.set(v, (acc.get(v) || 0) + 1), new Map() )
    .values()
].filter((v) => v > 1).length;

console.log(duplicate_count);

edited Jun 13, 2021 at 5:39

answered Jun 13, 2021 at 5:27

Ben Stephens

3,3711 gold badge7 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Guerric P · Accepted Answer · 2021-06-12 22:59:39Z

0

You could map to concatenate the numbers and strings, then sort. Finally, reduce the array to the duplicates count.

const input = [
  [2, "sk"],
  [3, "df"],
  [7, "uz"],
  [3, "df"],
  [7, "gh"],
  [7, "df"],
];

const result = input
  .map(([number, string]) => number + string)
  .sort()
  .reduce(
    (acc, cur, i, { [i - 1]: last }) => (cur === last ? acc + 1 : acc),
    0
  );

console.log(`Count: ${result}${result && ' Alert duplicate data found'}`);

answered Jun 12, 2021 at 22:59

Guerric P

32k6 gold badges61 silver badges109 bronze badges

Comments

Kinglish · Accepted Answer · 2021-06-12 23:19:59Z

0

    let arr =[[2,"sk"],[3,"df"],[7,"uz"],[3,"df"],[7,"gh"],[2,"sk"],[7,"uz"]]
    
    function getNumDupes(a) {
       return a.length-
    arr.reduce((b,a)=>{if (!b.includes(a.join(""))) b.push(a.join("")); return b;},[]).length 
    }
    
    console.log(getNumDupes(arr) + ' duplicates found');

answered Jun 12, 2021 at 23:19

Kinglish

23.7k4 gold badges25 silver badges43 bronze badges

Comments

Rajdeep D · Accepted Answer · 2021-06-12 23:20:49Z

0

You can use forEach to iterate the array and then filter and check length if found more than 1, set an entry into Map which holds a key value pair and will keep 1 entry for same key and then can check the size.

let arr =[[2,"sk"],[3,"df"],[7,"uz"],[3,"df"],[7,"gh"]];

let map = new Map();
arr.forEach(e1 => 
                 arr.filter(e2 => e1[0]===e2[0] && e1[1]===e2[1]).length > 1
                 ? map.set(`${e1[0]}-${e1[1]}`,1) 
                 : null
            );

console.log(`${map.size} duplicate found`);

answered Jun 12, 2021 at 23:20

Rajdeep D

3,9201 gold badge12 silver badges18 bronze badges

Collectives™ on Stack Overflow

Need to find or count duplicates in multidimensional array

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related