如何计算多维数组中每个唯一数组的数量？ 的PHP

Question

I'd like to build a simple shopping cart using arrays. I need to display each unique item in the shopping cart aswell as the quantity of each item along side.

My initial cart array might look like this:

$cart=

array(

         array(2003,100,"Table")
        ,array(2003,100,"Table")
        ,array(2003,100,"Table")
        ,array(2004,200,"Chair")
        ,array(2004,200,"Chair")

      );

The first value in each array is the product_id, then the price & then the product name.

How do I print each unique item once aswell as the quantity of each along side?

Thanks in advance.

Answer 1

$new_cart = array();

foreach($cart as $product) {
    if(!isset($new_cart[$product[0]])) {
      $new_cart[$product[0]] = array('quantity' => 1, 'label' => $product[2], 'price'        => $product[1]);
    }
    else {
      $new_cart[$product[0]]['quantity']++;
    }
}

I strongly suggest using associative arrays for this though. Your problem is the way you are storing the values. Try using something like this:

$cart_items = array(
  2004 => array('quantity' => 3, 'label' => 'Leather Chair', 'price' => 200),
  2901 => array('quantity' => 1, 'label' => 'Office Desk', 'price' => 1200),

);

When a user updates a quantity or adds an existing product simply increment the quantity.

Answer 2

You could simply iterate the array and use the product ID as key to count the amounts:

$amounts = array();
foreach ($cart as $item) {
    if (!isset($amounts[$item[0]])) $amounts[$item[0]] = 0;
    $amounts[$item[0]]++;
}

But it would be easier if your cart just stores the product IDs and amounts, so:

array(
    2003 => 3,
    2004 => 2
)

This is actually what the algorithm above is doing. But with this, you have all the information you need (product ID and amount).