PHP Program to Count Number of Vowels in a String

Given a String, the task is to count the number of Vowels in a given string in PHP. Counting the number of vowels in a string is a common programming task, often encountered in text processing and data analysis. Here, we will cover three common scenarios for counting the number of Vowels in a String.

Using a Loop and in_array() function

One straightforward approach is to iterate through each character in the string and check if it is a vowel using in_array() function.

Example: The below example illustrates the total Count of the Number of Vowels in a String using a Loop and in_array() function.

PHP

<?php

function countVowels($str)
{
    $str = strtolower($str);
    $vowelCount = 0;

    for ($i = 0; $i < strlen($str); $i++) {
        if (in_array($str[$i], ["a", "e", "i", "o", "u"])) {
            $vowelCount++;
        }
    }

    return $vowelCount;
}

// Driver code
$str = "GeeksforGeeks";
$vowelsCount = countVowels($str);

echo "Number of vowels: " . $vowelsCount;

?>

Output

Number of vowels: 5

Using Regular Expressions

Regular expressions provide a concise way to match patterns in strings. The following example uses a regular expression to count the vowels.

Example: The below example illustrates the total Count of the Number of Vowels in a String using Regular Expressions.

PHP

<?php
function countVowels($str)
{
    // Case-insensitive match for vowels
    preg_match_all("/[aeiou]/i", $str, $matches);
    return count($matches[0]);
}

// Driver code
$str = "GeeksforGeeks";
$vowelsCount = countVowels($str);

echo "Number of vowels: " . $vowelsCount;

?>

Output

Number of vowels: 5

Using str_ireplace() and strlen() Functions

Another approach is to replace all vowels in the string with an empty string using str_ireplace and then calculate the length of the resulting string.

Example: The below example illustrates the total Count of the Number of Vowels in a String using str_ireplace() and strlen() Functions.

PHP

<?php
function countVowels($str)
{
    $strWithoutVowels =
          str_ireplace(["a", "e", "i", "o", "u"], "", $str);
    return strlen($str) - strlen($strWithoutVowels);
}

// Driver code
$str = "GeeksforGeeks";
$vowelsCount = countVowels($str);

echo "Number of vowels: " . $vowelsCount;

?>

Output

Number of vowels: 5