将PHP for循环转换为for each循环

我对算法不太熟悉有人能帮我把这个for循环转换成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;
    }
}

for（$i=0；$igetBookID（）==$book->getId（））{
$newQuantity=$currentCartBookItem->getQuantity（）+$quantity；
$currentCartBookItem->setQuantity（$newQuantity）；
$isItemAlreadyExists=true；
}
}

更新

感谢@castis的建议。循环可迭代变量时，可以直接使用

$currentCartBookItem

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

---

$cartbooksitems作为$currentCartbooksitem

将需要较少的代码更改。将其

$cartbooksitems作为$currentCartbooksitem

进一步简化。@castis Thank updated:）Thank alot的效果非常好！！！这里出现的第一个问题是：为什么？

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

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

//or

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