<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
$pizzas = array(
    'pizza 1' => array('ost','tomat','skinke','oksekød','ananas'),
    'pizza 2' => array('ost','tomat','bacon','kapers','salat'),
    'pizza 3' => array('tomat','salat','ananas')
);

function find_best_matches($pizzas, $included, $excluded = array()) {
    $result = array();
    foreach($pizzas as $name => $ingredients) {
        if(count(array_intersect($ingredients, $excluded)) === 0) {
            $score = count(array_intersect($ingredients, $included))/count($included);
            if($score > 0) {
                $result[$name] = $score;
            }
        }
    }
    arsort($result);
    return $result; 
}

function test($included, $excluded = array()) {
    global $pizzas;
    $result = find_best_matches($pizzas, $included, $excluded);
    echo implode('+',$included) . ":\r\n";  
    foreach($result as $pizza => $score) {
        echo "$pizza : $score\r\n";
    }
}

test(array('ost','tomat'));
test(array('tomat'));
test(array('ost','tomat','skinke'));
test(array('ost','tomat','skinke','bacon','oksekød','ananas'));
test(array('ost','skinke','bacon'));
test(array('ost','skinke','bacon'), array('ananas'));

?>