将 PHP for 循环转换为 foreach [关闭]

我对算法不太熟悉，有人可以帮我把这个 for 循环转换为 foreach 吗

for($i = 0; $i < count($cartBookItems); $i++) {
    $currentCartBookItem = $cartBookItems[$i];
    if($currentCartBookItem->getBookID() == $book->getId()) {
        $newQuantity = $currentCartBookItem->getQuantity() + $quantity;
        $currentCartBookItem->setQuantity($newQuantity);
        $isItemAlreadyExists = true;
    }
}

foreach($cartBookItems as $each_book_item) {
    $currentCartBookItem = $each_book_item;
       if($currentCartBookItem->getBookID() == $book->getId()) {
             $newQuantity = $currentCartBookItem->getQuantity() + $quantity;
             $currentCartBookItem->setQuantity($newQuantity);
             $isItemAlreadyExists = true;             
       }
}

UPDATE

感谢@castis 的建议。你可以直接拥有$currentCartBookItem当你循环可迭代变量时。

foreach($cartBookItems as $currentCartBookItem ) {
       if($currentCartBookItem->getBookID() == $book->getId()) {
             $newQuantity = $currentCartBookItem->getQuantity() + $quantity;
             $currentCartBookItem->setQuantity($newQuantity);
             $isItemAlreadyExists = true;             
       }
}