sparse arrays

<?php

    $string = ['aca','aca','aca', 'aab', 'aaa', 'aa'];
    $query = ['aaa','aa','abba', 'aas'];
    $result = array_fill_keys($query, 0);

    //show String
    echo "String = ".count($string)."<br>";
    foreach ($string as $val){
        echo $val."<br>";
    };
    echo "<hr>";

    //Show query
    echo "Query = ".count($query)."<br>";
    foreach ($query as $val){
        echo $val."<br>";
    };
    echo "<hr>";

    //Process
    for($i=0; $i<count($string); $i++){
        for ($j=0; $j< count($query); $j++){
            if($query[$j]==$string[$i]){
                $result[$query[$j]] += 1;
            }
            else {
                $result[$query[$j]] += 0;
            }
        }
    }

    echo "Result = <br>";
    foreach ($result as $val){
        echo $val."  ";
    };

?>