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<html><body>function countLetters($matches) { return $matches[0] . '[' . strlen($matches[0]) . 'letter]';}function countDigits($matches) { return $matches[0] . '[' . strlen($matches[0]) . 'digit]';}$input = "There are 365 days in a year.";$patterns = [ '/\b[a-z]+\b/i' => 'countLetters', '/\b[0-9]+\b/' => 'countDigits'];$result = preg_replace_callback_array($patterns, $input);echo $result;</body></html>
There[5letter] are[3letter] 365[3digit] days[4letter] in[2letter] a[1letter] year[4letter].