How can PHP developers effectively troubleshoot issues with preg_match_all not returning expected results?

Issue: If preg_match_all is not returning expected results, it could be due to incorrect regular expression patterns or incorrect usage of the function. To troubleshoot this issue, developers should carefully review their regular expression patterns, ensure proper escaping of special characters, and check if the input string matches the pattern. 

// Example code snippet to troubleshoot preg_match_all not returning expected results
$pattern = '/[0-9]+/';
$input = 'abc123def456ghi';

if (preg_match_all($pattern, $input, $matches)) {
    // Output the matches
    print_r($matches);
} else {
    echo 'No matches found.';
}

Keywords

PHP preg_match_all troubleshooting regular expressions debugging

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