What are some potential pitfalls of using str_replace to modify voucher codes in a CSV file in PHP?

Using str_replace to modify voucher codes in a CSV file in PHP can be risky because it may unintentionally replace parts of the code that are not supposed to be modified. To avoid this, it is recommended to use a more precise method like regular expressions to target specific patterns within the voucher codes.

// Example of using regular expressions to modify voucher codes in a CSV file
$file = 'vouchers.csv';
$csv = file_get_contents($file);

// Define the pattern to match voucher codes
$pattern = '/\b[A-Z0-9]{8}\b/';

// Use preg_replace to modify voucher codes while preserving their format
$csv_modified = preg_replace($pattern, 'NEW_CODE', $csv);

file_put_contents($file, $csv_modified);