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js find duplicates in array and count of numbers

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MAKSTYLE119 answered on May 12, 2020 Popularity 10/10 Helpfulness 5/10

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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 find javascript numbers

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Contributed on Sep 03 2022

MAKSTYLE119

0 Answers Avg Quality 2/10

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count duplicate elements in array javascript

Comment

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

find duplicate values in array javascript

Comment

const findDuplicates = (arr) => {
  let sorted_arr = arr.slice().sort(); // You can define the comparing function here. 
  // JS by default uses a crappy string compare.
  // (we use slice to clone the array so the
  // original array won't be modified)
  let results = [];
  for (let i = 0; i < sorted_arr.length - 1; i++) {
    if (sorted_arr[i + 1] == sorted_arr[i]) {
      results.push(sorted_arr[i]);
    }
  }
  return results;
}

let duplicatedArray = [9, 4, 111, 2, 3, 4, 9, 5, 7];
console.log(`The duplicates in ${duplicatedArray} are ${findDuplicates(duplicatedArray)}`);

Popularity 10/10 Helpfulness 5/10 Language javascript

Source: stackoverflow.com

Tags: find

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Contributed on Jan 09 2021

Fancy Fish

0 Answers Avg Quality 2/10

how to get duplicate values from array in javascript

Comment

var input = [1, 2, 3, 1, 3, 1];

var duplicates = input.reduce(function(acc, el, i, arr) {
  if (arr.indexOf(el) !== i && acc.indexOf(el) < 0) acc.push(el); return acc;
}, []);

document.write(duplicates); // = 1,3 (actual array == [1, 3])

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: stackoverflow.com

Tags: get

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Contributed on Jun 19 2020

Restu Wahyu Saputra

0 Answers Avg Quality 2/10

duplicate numbers in an array javascript

Comment

[1, 1, 2, 2, 3].filter((element, index, array) => array.indexOf(element) !== index) // [1, 2]

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Nov 10 2020

Smarty Hearty

0 Answers Avg Quality 2/10

how to get duplicate values from array in javascript

Comment

const names = ['Mike', 'Matt', 'Nancy', 'Adam', 'Jenny', 'Nancy', 'Carl']

const count = names =>
  names.reduce((a, b) => ({ ...a,
    [b]: (a[b] || 0) + 1
  }), {}) // don't forget to initialize the accumulator

const duplicates = dict =>
  Object.keys(dict).filter((a) => dict[a] > 1)

console.log(count(names)) // { Mike: 1, Matt: 1, Nancy: 2, Adam: 1, Jenny: 1, Carl: 1 }
console.log(duplicates(count(names))) // [ 'Nancy' ]

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: stackoverflow.com

Tags: get

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Contributed on Jun 19 2020

Restu Wahyu Saputra

0 Answers Avg Quality 2/10

how to get duplicate values from array in javascript

Comment

const arr = ["q", "w", "w", "e", "i", "u", "r"]
arr.reduce((acc, cur) => { 
  if(acc[cur]) {
    acc.duplicates.push(cur)
  } else {
    acc[cur] = true //anything could go here
  }
}, { duplicates: [] })

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: stackoverflow.com

Tags: get

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Contributed on Jun 19 2020

Restu Wahyu Saputra

0 Answers Avg Quality 2/10

Find duplicate or repeat elements in js array

Comment

-1

function findUniq(arr) {
  return arr.find(n => arr.indexOf(n) === arr.lastIndexOf(n));
}

console.log(findUniq([ 0, 1, 0 ]))
console.log(findUniq([ 1, 1, 1, 2, 1, 1 ]))
console.log(findUniq([ 3, 10, 3, 3, 3 ]))
console.log(findUniq([ 7, 7, 7, 20, 7, 7, 7 ]))

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: elements element

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Contributed on Oct 11 2021

Wide-eyed Wolf

0 Answers Avg Quality 2/10

counting duplicate values javascript

Comment

var counts = {};
your_array.forEach(function(x) { counts[x] = (counts[x] || 0)+1; });

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: counting countin

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Contributed on May 12 2020

Xanthous Xenomorph

0 Answers Avg Quality 2/10

find duplicate values in array javascript

Comment

const findDuplicates = (arr) => {
  let sorted_arr = arr.slice().sort(); // You can define the comparing function here. 
  // JS by default uses a crappy string compare.
  // (we use slice to clone the array so the
  // original array won't be modified)
  let results = [];
  for (let i = 0; i < sorted_arr.length - 1; i++) {
    if (sorted_arr[i + 1] == sorted_arr[i]) {
      results.push(sorted_arr[i]);
    }
  }
  return results;
}

let duplicatedArray = [9, 4, 111, 2, 3, 9, 4, 5, 7];
console.log(`The duplicates in ${duplicatedArray} are ${findDuplicates(duplicatedArray)}`);

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: stackoverflow.com

Tags: find

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Contributed on Jan 09 2021

Fancy Fish

0 Answers Avg Quality 2/10

js find duplicates in array and count of numbers

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