Shows 20 most popular words in a text file

most_popular.php

<?
$book = file_get_contents('book.txt');

$book = strtolower($book);
$book = str_replace(array('.', ',', ':', ';', '"', "'", '?', '!', '-', '`'), '', $book);

$words = explode(' ', $book);

$stats = array_count_values($words);

arsort($stats);

echo count($words).' words in book<br><br>';

echo '20 most popular words:<br><br>';

$i = 0;
foreach($stats as $word => $counter) {
	echo ++$i.' <a href="http://translate.google.com/#es|en|'.$word.'">'.$word.'</a> ('.$counter.' times)<br>';
	if($i >= 20) {
		break;
	}
}