Need To Find Or Count Duplicates In Multidimensional Array

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

Solution 1:

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 - newSet( 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), newMap() )
    .values()
].filter((v) => v > 1).length;

console.log(duplicate_count);

Solution 2:

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'}`);

Solution 3:

let arr =[[2,"sk"],[3,"df"],[7,"uz"],[3,"df"],[7,"gh"],[2,"sk"],[7,"uz"]]
    
    functiongetNumDupes(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');

Solution 4:

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 = newMap();
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`);