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<?php $sentence = 'Jumpy Qbert grawlix'; $usage = count_chars(strtolower($sentence), 3); $alphabet = range('a', 'z'); var_export([ 'Sentence' => $sentence, 'Total Length' => strlen($sentence), 'Alphabetical Length' => preg_match_all('~[a-z]~', $sentence, $letters), 'Unused Letters' => array_diff($alphabet, $letters[0]), 'Duplicated Letters' => array_diff(array_count_values($letters[0]), [1]), ]);
based on IUTV1