count of elements in array of jquery

Question

I'm having array in Jquery like following,

[125, "321", "kar", 125, "sho", "sho", 12, 125, "32", 32]

It's having duplicate. I want count of each and every element in array(associative array).

Try getting the unique values from the array first: http://stackoverflow.com/questions/1960473/unique-values-in-an-array, then use `.length` of the new array. — Mottie, Dec 24 '15 at 13:46
Check following post: http://stackoverflow.com/questions/34396767/sort-array-by-occurrence-of-its-elements/34396876#34396876 — Rajesh, Dec 24 '15 at 13:50
`array in Jquery` - correction, that's a plain ol' javascript array - there's no such animal as a jquery array — Jaromanda X, Dec 24 '15 at 13:52
You aren't manipulating the dom so you don't need jQuery, yes there are neat little functions like each that cut a few lines out of using an actual for loop but really it's overkill. You don't have an associative array, you have an array. Check out the docs at the mozilla developer network for javascript they are really useful for learning how to use javascript: https://developer.mozilla.org/en-US/docs/Web/JavaScript — scrappedcola, Dec 24 '15 at 13:53

score 1 · Answer 1 · answered Dec 24 '15 at 13:48

Try following Script

var Items = [125, "321", "kar", 125, "sho", "sho", 12, 125, "32", 32],
    counts = {};

jQuery.each(Items , function(key,value) {
  if (!counts.hasOwnProperty(value)) {
    counts[value] = 1;
  } else {
    counts[value]++;
  }
});

score 1 · Answer 2 · answered Dec 24 '15 at 13:51

Populate a 'frequencies' object using values from the arry

var frequencies = {};
[125, "321", "kar", 125, "sho", "sho", 12, 125, "32", 32].map( 
  function (v) {
    if (frequencies[v]) { frequencies[v] += 1; }
    else { frequencies[v] = 1; }
    return v;
}, frequencies);

var result = document.querySelector('#result');
result.textContent = JSON.stringify(frequencies, 0, 2) +
                     '\nAnd unique \'values\' from the frequencies object:\n[' +
                     Object.keys(frequencies).join(', ') + ']';

<pre id="result"></pre>

score 1 · Answer 3 · answered Dec 24 '15 at 14:08

1

A very short version with Array.prototype.reduce()

var array = [125, "321", "kar", 125, "sho", "sho", 12, 125, "32", 32],
    count = array.reduce(function (r, a) {
        r[a] = (r[a] || 0) + 1;
        return r;
    }, {});

document.write('<pre>' + JSON.stringify(count, 0, 4) + '</pre>');

answered Dec 24 '15 at 14:08

Nina Scholz

376,160
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even shorter: `return (r[a] = (r[a] || 0) + 1) && r;` ;) – KooiInc Dec 24 '15 at 16:23
@KooiInc, too much parenthesis. – Nina Scholz Dec 24 '15 at 16:35
i know, the assignment needs the parenthesis. but it makes the code not more readable, as it is. – Nina Scholz Dec 24 '15 at 16:47

Xotic750 · Answer 4 · 2015-12-24T14:35:43.460

This solution will give you a count of every element (whatever it is), except it will not differentiate between +0 and -0 (SameValueZero).

var array = [125, "321", "kar", 125, "sho", "sho", 12, 125, "32", 32];
var counts = array.reduce(function(acc, item) {
  if (acc.has(item)) {
    acc.set(item, acc.get(item) + 1);
  } else {
    acc.set(item, 1);
  }
  return acc;
}, new Map());
document.getElementById('out').textContent = JSON.stringify(Array.from(counts), null, 2);
console.log(counts);

<script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.4.1/es5-shim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/json3/3.3.2/json3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/es6-shim/0.34.0/es6-shim.js"></script>
<pre id="out"></pre>

And if you want an array of the unique values.

var array = [125, "321", "kar", 125, "sho", "sho", 12, 125, "32", 32];
var unique = Array.from(new Set(array));
document.getElementById('out').textContent = JSON.stringify(unique, null, 2);
console.log(unique);

<script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.4.1/es5-shim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/json3/3.3.2/json3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/es6-shim/0.34.0/es6-shim.js"></script>
<pre id="out"></pre>

count of elements in array of jquery

4 Answers4