Last Updated: August 03, 2016

Vowel Count (JS Algorithm)

Basic algorithm that takes in a string and returns the count of vowels that appear in the string. Uses a nested for loop, which isn't optimal for larger strings. I wonder if anybody has a better solution?

function vowel_count(str) {
 'use strict';

 if(typeof str != 'string') {
 return false;
 }

 var count = 0;
 var pattern = /[aeiou]/i;

 for(var i = 0; i < str.length; i++) {
 if(str[i].match(pattern)) {
 count++;
 }
 }

 return count;
}

var sentence = 'This should have 9 vowels in it';

var output = vowel_count(sentence);

console.log(output);

#javascript

#algorithm

Written by shinjukudev

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3 Responses

Add your response

jeffcheung

you don't need to regexp.match each character. regexp.match returns all the matches in the array, and you can get the length of the array once without a for loop.

function vowel_count(str)
{
 'use strict';

 if(typeof str != 'string') {
 return false;
 }

 var count = 0;
 var pattern = /[aeiou]/ig;
 var matches = str.match(pattern);
 return matches != null? matches.length:0;
}

over 1 year ago ·

shinjukudev

@jeffcheung Hey! Thanks for the feedback! That's a really good point

over 1 year ago ·

shinjukudev

@jeffcheung In that case, we can get rid of var count = 0 as well :)

over 1 year ago ·