Finding the occurrences of elements in an array using JavaScript

Question

Finding the occurrences of elements in an array using JavaScript

While browsing Stack Overflow, I stumbled upon a question that has yet to be answered: How can I count the occurrences of elements in a specific array using JavaScript?.

let array = [6, 1, 5, 1, 1, 8, 2, 4, 6, 0] // Elements in array

getOccurrence(array) /* returns
    [
        {occurrence: x, item: array[y]},
        {occurrence: ..., item: ...},
        {...},
    ]

    where 'x' is the frequency of an item in the array.
*/

If there are any algorithms that can achieve this, please advise.

javascript arrays

Answer 1

Answer №1

Here is a suggested approach for solving this problem:

function findItemFrequencies(arr) {
    let frequencies = [],
        iterator = 0,
        len = arr.length;

    for (iterator; iterator != len; iterator += 1) {
        let item = arr[iterator],
            freqIterator = frequencies.length;

        if (
            (function() {
                while (freqIterator)
                    if (frequencies[freqIterator -= 1].item === item)
                        return !0
            })()
        ) {
            if (frequencies.length > freqIterator)
                frequencies[freqIterator].occurrence += 1
        }

        else
            frequencies.push({occurrence: 1, item: item})
    }

    return frequencies
}

Answer 2

Here is a suggested approach for solving this problem:

function findItemFrequencies(arr) {
    let frequencies = [],
        iterator = 0,
        len = arr.length;

    for (iterator; iterator != len; iterator += 1) {
        let item = arr[iterator],
            freqIterator = frequencies.length;

        if (
            (function() {
                while (freqIterator)
                    if (frequencies[freqIterator -= 1].item === item)
                        return !0
            })()
        ) {
            if (frequencies.length > freqIterator)
                frequencies[freqIterator].occurrence += 1
        }

        else
            frequencies.push({occurrence: 1, item: item})
    }

    return frequencies
}

Finding the occurrences of elements in an array using JavaScript

Answer №1

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