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In an array we can store different elements, those elements can be integer, character, string or anything. And there could be repetition of elements in an array. This article discusses the method to find the number of occurrences of an element in the array. Number of occurrence means how many times the element occurred or appeared in the array.

Approach

To find the number of occurrences we have to write a correct function  that can find it. The function required for this operation is only one line function.

  • Create a function which takes an array and value of element as parameter.
  • And write the mathematical expression  for  counting the number of occurrences of elements.
  • now just pass the array and the element by console.log() function to find out the number of occurrences of the element in  the array.

Program


const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a), 0);
console.log(countOccurrences([1, 1, 2, 1, 2, 3], 1));
console.log(countOccurrences([1, 1, 2, 1, 2, 3], 2));
console.log(countOccurrences([1, 1, 2, 1, 2, 3], 3));

Output

In the above example we entered the array [1, 1, 2, 1, 2, 3] and we looked for the element ‘1’. The program completes its loop and shows the number of occurrences  as 3, since it occurred 3 times in  our array.

Hope this will help.
 

100 points
7 4