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PHP Code Challenge #2 Find the first non-repeating character in a string:

Here's a PHP code snippet to find the first non-repeating character in a string:

<?php

function firstNonRepeatingCharacter($str) {

    $charCount = array();


    // Count occurrences of each character in the string

    for ($i = 0; $i < strlen($str); $i++) {

        $char = $str[$i];

        if (isset($charCount[$char])) {

            $charCount[$char]++;

        } else {

            $charCount[$char] = 1;

        }

    }


    // Find the first non-repeating character

    for ($i = 0; $i < strlen($str); $i++) {

        $char = $str[$i];

        if ($charCount[$char] === 1) {

            return $char;

        }

    }


    // If no non-repeating character is found

    return null;

}


// Example usage:

$string = "aabbccdeeff";

$result = firstNonRepeatingCharacter($string);


if ($result !== null) {

    echo "The first non-repeating character is: $result\n";

} else {

    echo "No non-repeating character found in the string.\n";

}


?>

 

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