カードの振り分けの実装

CardManager.php

<?php

class CardManager {

    /**
     *
     * @param integer $deal_num
     * @param String $card
     *
     * @return array
     */
    public function deal($deal_num, $card)
    {
        $result = array_fill(0, $deal_num, '');

        $len = strlen($card);
        $roop = $len - ($len % $deal_num);
        for ($i = 0; $i < $roop; $i++) {
            $index = $i % $deal_num;
            $result[$index] .= substr($card, $i, 1);
         }

        return $result;
    }
}