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javascript how to check the indexes of duplicates elements in an array

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Al-khatab Yaseen answered on January 1, 2021 Popularity 9/10 Helpfulness 4/10

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javascript how to check the indexes of duplicates elements in an array

Comment

// A method to find a duplicate value in an array and the index of the duplicates
// array can be any data type
const arry = ["1", "2", "3", "1"];
let set = new Set();
for (let i = 0; i < arry.length; i++) {
  let pastSize = set.size;
  set.add(arry[i]);
  let newSize = set.size;
  if (pastSize == newSize) {
    console.log("The array has duplicates at index: ", i);
  }
}

Popularity 9/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: elements find javascript

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Contributed on Oct 24 2022

Al-khatab Yaseen

0 Answers Avg Quality 2/10

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count duplicate elements in array javascript

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const counts = {};
const sampleArray = ["1", "5", "9", "14", "5", "22", "48", "25", "22", "20", "9" ,"13"]
sampleArray.forEach(function (x) { counts[x] = (counts[x] || 0) + 1; });
console.log(counts)
 // output: {
  '1': 1,
  '5': 2,
  '9': 2,
  '13': 1,
  '14': 1,
  '20': 1,
  '22': 2,
  '25': 1,
  '48': 1
}

Popularity 10/10 Helpfulness 5/10 Language javascript

Source: stackoverflow.com

Tags: count coun

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Contributed on May 18 2022

Mizanur Rahman

0 Answers Avg Quality 2/10

js find duplicates in array and count of numbers

Comment

const arr = ["a", "b", "c", "d", "e", "a", "b", "c", "f", "g", "h", "h", "h", "e", "a"]
const counts = {};
arr.forEach((x) => {
  counts[x] = (counts[x] || 0) + 1;
});
console.log(counts)

Popularity 10/10 Helpfulness 5/10 Language javascript

Source: thewebdev.info

Tags: count coun

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Contributed on Sep 03 2022

MAKSTYLE119

0 Answers Avg Quality 2/10

check duplicate value exist in array javascript

Comment

function hasDuplicates(array) {
  // create a set to store unique values
  const uniqueValues = new Set();

  // loop through the array
  for (let i = 0; i < array.length; i++) {
    // if the value is not in the set, add it
    if (!uniqueValues.has(array[i])) {
      uniqueValues.add(array[i]);
    } else {
      // if the value is already in the set, return true
      return true;
    }
  }

  // if the loop completes and there are no duplicates, return false
  return false;
}

const numbers = [1, 2, 3, 4, 5];
const hasDuplicates = hasDuplicates(numbers); // returns false

const letters = ['a', 'b', 'c', 'b'];
const hasDuplicates = hasDuplicates(letters); // returns true

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: elements element

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Contributed on Dec 05 2022

Mehedi Islam Ripon

0 Answers Avg Quality 2/10

check for duplicates in array javascript

Comment

[1, 2, 3].every((e, i, a) => a.indexOf(e) === i) // true

[1, 2, 1].every((e, i, a) => a.indexOf(e) === i) // false

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: stackoverflow.com

Tags: javascript j

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Contributed on Jan 01 2021

Repulsive Rhinoceros

0 Answers Avg Quality 2/10

javascript check for duplicates in array

Comment

function checkIfDuplicateExists(w){
    return new Set(w).size !== w.length 
}

console.log(
    checkIfDuplicateExists(["a", "b", "c", "a"])
// true
);

console.log(
    checkIfDuplicateExists(["a", "b", "c"]))
//false

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Sep 16 2021

Sbeajy

0 Answers Avg Quality 2/10

javascript how to check the indexes of duplicates elements in an array

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