Determine the frequency of each element in the array

Given an arbitrary array, the goal is to determine the unique elements in the array along with their respective count. While I have managed to identify the unique elements within the array, I am struggling to establish a way to associate each element with its count. Any suggestions on how to achieve this without utilizing functions? I am new and haven't delved into functions yet.

var arr = [3, 4, 4, 3, 3];
var new_arr = [];
for (i = 0; i < arr.length; i++) {
if (new_arr.includes(arr[i])) {
// pass
} else {
new_arr.push(arr[i]);
}
}
console.log(new_arr);

javascriptarrayscount

Answer №1

Instead of using an Array, opt for an Object to maintain the count. Assign the number as the `key` and its count as the `value`.

Check out Array#reduce method for reference.

const res = [3, 4, 4, 3, 3].reduce((acc,cur)=>{
  
  if(acc[cur]) acc[cur]++;
  else acc[cur] = 1;
  return acc;

}, {});

console.log(res);

Alternatively, achieve the same without utilizing any methods:

var arr = [3, 4, 4, 3, 3];
var new_arr = {};
for (i = 0; i < arr.length; i++) {
  if (new_arr[arr[i]]) {
    new_arr[arr[i]]++;
  } else {
    new_arr[arr[i]] = 1;
  }
}
console.log(new_arr);

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