gistfile1.txt

	function extract_common_words($string, $max_count = 10) {
		$string = preg_replace('/ss+/i', '', $string); // replace whitespace
		$string = preg_replace('/[^a-zA-Z -]/', '', $string); // only take alphabet characters, but keep the spaces and dashes too…
		$string = strtolower($string); // make it lowercase

		$matched = array();
		$tok = strtok($string, " ");

		while ($tok !== false) {
			if ( !empty($tok) && !in_array(strtolower($tok), $this->stopWords) && strlen($tok) > 3 ) {
				$matched[] = $tok;
			}
			$tok = strtok(" ");
		}

		$frequency = array_count_values($matched);
		arsort($frequency);

		$keywords = array_slice($frequency, 0, $max_count);
		return $keywords;
	}