What are potential pitfalls of using string comparisons for linking words in PHP?

When using string comparisons for linking words in PHP, potential pitfalls include case sensitivity issues, leading to mismatches if the cases do not match exactly. Additionally, extra whitespace or special characters can cause mismatches as well. To solve this, it is recommended to normalize the strings by converting them to lowercase and removing any extra whitespace or special characters before comparing them.

$linking_word1 = "Hello";
$linking_word2 = "  hello ";

// Normalize the strings by converting to lowercase and removing extra whitespace
$normalized_word1 = strtolower(trim($linking_word1));
$normalized_word2 = strtolower(trim($linking_word2));

// Compare the normalized strings
if ($normalized_word1 === $normalized_word2) {
    echo "Linking words match!";
} else {
    echo "Linking words do not match.";
}