How can regular expressions be used to search for specific patterns in a string in PHP?

Regular expressions can be used in PHP to search for specific patterns in a string by using functions like preg_match() or preg_match_all(). These functions allow you to define a pattern using regular expression syntax and then search for that pattern within a given string. This can be useful for tasks like validating input, extracting data, or replacing text based on certain criteria. 

// Example of using regular expressions to search for a specific pattern in a string
$string = "The quick brown fox jumps over the lazy dog";
$pattern = '/\b\w{5}\b/'; // Search for words that are exactly 5 characters long

if (preg_match_all($pattern, $string, $matches)) {
    echo "Matches found: ";
    print_r($matches[0]);
} else {
    echo "No matches found.";
}

Keywords

Regular expressions patterns string PHP search

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