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Algorithm 101: 13 Ways to Count Vowels in a String

NJOKU SAMSON EBERE
I love providing solutions to real world problems. When I am not coding, I enjoy movies, hanging out and working out.
Updated on ・3 min read

In this episode of Algorithm 101, we will be looking at thirteen (13) different ways to count the vowels in a given string.


vowelsCounter('njoku'); // 2

vowelsCounter('njoku samson ebere'); // 7

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Prerequisite

This article assumes that you have basic understanding of javascript's string methods and array methods.

Let's count the vowels in a given string using:

  • split() method, for...of loop and if...statement
      function vowelsCounter(text) {
        let splittedText = text.toLowerCase().split("");
        let counter = 0;

        for (char of splittedText) {
          if (
            char === "a" ||
            char === "e" ||
            char === "i" ||
            char === "o" ||
            char === "u"
          ) {
            counter++;
          }
        }

        return counter;
      }
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  • split() method, includes method, for...of loop and if...statement
      function vowelsCounter(text) {
        let splittedText = text.toLowerCase().split("");
        let counter = 0;
        let vowels = ["a", "e", "i", "o", "u"];

        for (char of splittedText) {
          if (vowels.includes(char)) {
            counter++;
          }
        }

        return counter;
      }
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  • spread operator, includes method, for...of loop and if...statement
      function vowelsCounter(text) {
        let counter = 0;
        let vowels = ["a", "e", "i", "o", "u"];

        for (char of [...text]) {
          if (vowels.includes(char)) {
            counter++;
          }
        }

        return counter;
      }
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  • spread operator, for...of loop and if...statement
      function vowelsCounter(text) {
        let counter = 0;

        for (char of [...text]) {
          if (
            char === "a" ||
            char === "e" ||
            char === "i" ||
            char === "o" ||
            char === "u"
          ) {
            counter++;
          }
        }

        return counter;
      }
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  • split() method, for...in loop and if...statement
      function vowelsCounter(text) {
        let splittedText = text.toLowerCase().split("");
        let counter = 0;

        for (char in splittedText) {
          if (
            splittedText[char] === "a" ||
            splittedText[char] === "e" ||
            splittedText[char] === "i" ||
            splittedText[char] === "o" ||
            splittedText[char] === "u"
          ) {
            counter++;
          }
        }

        return counter;
      }
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  • split() method, includes() method, for...in loop and if...statement
      function vowelsCounter(text) {
        let splittedText = text.toLowerCase().split("");
        let counter = 0;
        let vowels = ["a", "e", "i", "o", "u"];

        for (char in splittedText) {
          if (vowels.includes(splittedText[char])) {
            counter++;
          }
        }

        return counter;
      }
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  • spread operator, includes() method, for...in loop and if...statement
      function vowelsCounter(text) {
        let counter = 0;
        let vowels = ["a", "e", "i", "o", "u"];

        for (char in [...text]) {
          if (vowels.includes(text[char])) {
            counter++;
          }
        }

        return counter;
      }
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  • spread operator, for...in loop and if...statement
      function vowelsCounter(text) {
        let counter = 0;

        for (char in [...text]) {
          if (
            text[char] === "a" ||
            text[char] === "e" ||
            text[char] === "i" ||
            text[char] === "o" ||
            text[char] === "u"
          ) {
            counter++;
          }
        }

        return counter;
      }
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  • spread operator, for...loop and if...statement
      function vowelsCounter(text) {
        let counter = 0;

        for (let i = 0; i <= [...text].length; i++) {
          if (
            text[i] === "a" ||
            text[i] === "e" ||
            text[i] === "i" ||
            text[i] === "o" ||
            text[i] === "u"
          ) {
            counter++;
          }
        }

        return counter;
      }
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  • spread operator, includes() method, for...loop and if...statement
      function vowelsCounter(text) {
        let counter = 0;
        let vowels = ["a", "e", "i", "o", "u"];

        for (let i = 0; i <= [...text].length; i++) {
          if (vowels.includes(text[i])) {
            counter++;
          }
        }

        return counter;
      }
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  • split() method, for... loop and if...statement
      function vowelsCounter(text) {
        let splittedText = text.toLowerCase().split("");
        let counter = 0;

        for (let i = 0; i <= splittedText.length; i++) {
          if (
            splittedText[i] === "a" ||
            splittedText[i] === "e" ||
            splittedText[i] === "i" ||
            splittedText[i] === "o" ||
            splittedText[i] === "u"
          ) {
            counter++;
          }
        }

        return counter;
      }
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  • split() method, includes() method, for... loop and if...statement
      function vowelsCounter(text) {
        let splittedText = text.toLowerCase().split("");
        let counter = 0;
        let vowels = ["a", "e", "i", "o", "u"];

        for (let i = 0; i <= splittedText.length; i++) {
          if (vowels.includes(splittedText[i])) {
            counter++;
          }
        }

        return counter;
      }
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  • regEx and if...statement
      function vowelsCounter(text) {
        let regEx = /[aeiou]/gi;
        let matchedVowels = text.match(regEx);

        if (matchedVowels) {
          return matchedVowels.length;
        }

        return 0;
      }
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Conclusion

There are many ways to solve problems programmatically. You are only limited by your imagination. I will love to know other ways you solved yours in the comment section.

If you have questions, comments or suggestions, please drop them in the comment section.

Up Next: Algorithm 101: 6 Ways to Find the Most Recurring Character in a String

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Thank You For Your Time.

Discussion (4)

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jsmitar profile image
JSmith AR • Edited

another simple solution

const vowelsCounter_ = str => str.split('').filter(ch => 'aeiouAEIOU'.includes(ch)).length
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ebereplenty profile image
NJOKU SAMSON EBERE Author

This is lovely too. Using split() and filter()

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jsmitar profile image
JSmith AR • Edited

I love the simple and shorts solutions.

const vowelsCounter = str => str.replace(/[^aeiou]/ig, '').length
vowelsCounter('njoku samson ebere')
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ebereplenty profile image
NJOKU SAMSON EBERE Author

Wow... using replace() and regEx. It's really short and straight to the point