Find all occurrences of word in array

Question

I'm trying to find the number of total occurrences of a word in an array.
Here I found a solution and altered it a bit:

var dataset = ["word", "a word", "another word"];
var search = "word";
var count = dataset.reduce(function(n, val) {
  return n + (val === search);
}, 0);

Here is the fiddle.

But, instead of 3 I only get 1. So it only finds the first element, which is just word. But how to find all elements, containing word?

Can you please answer whether you want this to count ["word times three word word", "word"]` as four occurrences, or just 2? If it should be four, this actually becomes a bit more complex than most of the answers that have been given. — Katana314, Apr 13 '16 at 20:16
@Katana314: In my case there won't be multiple occurrences of a word within an element of an array. — Evgenij Reznik, Apr 13 '16 at 20:19
My apologies, then, to the answerer that I downvoted. (Pretty much every answer had that issue, at which point I decided to clarify) — Katana314, Apr 13 '16 at 20:28

Abhi · Accepted Answer · 2016-04-13T20:29:55.510

1

Try this:

var dataset = ["word", "a word", "another word"];
var search = "word";
count = 0;

jQuery(dataset).each(function(i, v){ if(v.indexOf(search) != -1) {count ++} });

Here, count will be 3.

edited Apr 13 '16 at 20:29

answered Apr 13 '16 at 20:11

Abhi

4,123
6
45
77

Why did you switch to using jQuery.each? – TAGraves Apr 13 '16 at 20:11
This actually wouldn't account for `["word is word present word multiple word times word", "word"]` – Katana314 Apr 13 '16 at 20:14
@Katana314 As OP says in comments, it won't repeat the search string for him. – Abhi Apr 13 '16 at 20:27

score 0 · Answer 2 · answered Apr 13 '16 at 20:11

You have to use String.prototype.indexOf() that return the index of the first occurence of the substring in the string, or -1 if not found:

var dataset = ["word", "a word", "another word"];
var search = "word";
var count = dataset.reduce(function(n, val) {
  return n + (val.indexOf(search) > -1 ? 1 : 0);
}, 0);

score 0 · Answer 3 · answered Apr 13 '16 at 20:15

The operator === means: equal object and equal type.

If you are looking for each array element containing the 'search' word you need to use a different operator.

So, another possible approach, using filter and indexOf, is:

var dataset = ["word", "a word", "another word"];
var search = "word";
var count = dataset.filter(function(val) {
  return val.indexOf(search) != -1;
}).length;

document.write('N. words: ' + count)

score 0 · Answer 4 · answered Apr 13 '16 at 20:29

0

You could use String#indexOf.

var dataset = ["word", "a word", "another word"],
    search = "word",
    count = dataset.reduce(function(r, a) {
        return r + !!~a.indexOf(search);
    }, 0);

document.write(count);

answered Apr 13 '16 at 20:29

Nina Scholz

376,160
25
347
392

score 0 · Answer 5 · answered Nov 15 '22 at 16:32

Here is a one-line ES6 Arrow Function.

 const  countOccurrence = (arr,elem) =>  arr.filter((v) => v===elem).length;

Testing

const  countOccurrence = (arr,elem) =>  arr.filter((v) => v===elem).length;

//Testing
console.log(countOccurrence([1,2,3,4,5,6,1,8,9,1,1],1));
console.log(countOccurrence(['w','o','w'],'w'));
console.log(countOccurrence(['hello','world','hello'],'hello'));

Find all occurrences of word in array

5 Answers5