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find first repeating element in array js

Ameer Jamal answered on October 25, 2020 Popularity 5/10 Helpfulness 1/10

answer find first repeating element in array js

related first duplicate javascript

find first repeating element in array js

Comment

arr=[1,2,3,2,4,5,6,6]
arrnoRecur=[1,2,3,4]
function firstRecur(arr) {
  // create an empty hash table
  const hash = {};
  // iterate over the array
  for (let i = 0; i < arr.length; i++) {
    // check if the current element is already in the hash table
    if (hash[arr[i]]) {
      // if it is just return it
      return arr[i];
    } 
    else {
      // otherwise, Create the element key and set the value of element to true 
      hash[arr[i]] = true; // note that in JS when you say hash[arr[i]] = whatever 
      // if the hash[arr[i]] doesnt exist it will autmoatically make it
    }
  }
  
  // return undefined if no reoccurring element is found
  return undefined;
}

console.log(firstRecur(arrnoRecur))
console.log(firstRecur(arr))

Popularity 5/10 Helpfulness 1/10 Language javascript

Source: Grepper

Tags: element find javascript

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Contributed on Apr 03 2023

Ameer Jamal

0 Answers Avg Quality 2/10

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first duplicate javascript

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function firstDuplicate(a) {
    let data = [];
    
    for (dup of a) {
        if (data[dup]) {
            return dup
        } else {
            data[dup] = dup
        }
    }
    return -1
}

Popularity 9/10 Helpfulness 7/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Oct 25 2020

Arrogant Anteater

0 Answers Avg Quality 2/10

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find first repeating element in array js

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first duplicate javascript

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