PHP Count number of array items that exist in another array

Question

I'm stuck on how to count the items in my array

Code

// Product ID's to Search
$deposit_items = array( '4359', '4336', '4331', '4320' );

// Loop through the Cart Items
foreach ( $cart_object->get_cart() as $item_values ) {

    // Check if the cart contains items with the matching Product ID's
    if( in_array( $item_values['product_id'], $deposit_items )) {
        // Count number of products in Cart that have matching Product ID's 
    }
}

I need to return the number of items in the array that have Product ID's as listed in $deposit_items

Answer 1

Something like this

// Product ID's to Search
$deposit_items = array( '4359', '4336', '4331', '4320' );
$cart_items = $cart_object->get_cart();
$cart_product_ids = array_column($cart_items, 'product_id');

$count = count(array_intersect($cart_product_ids, $deposit_items ));

For example

// Product ID's to Search
$deposit_items = array( '4359', '4336', '4331', '4320' );
$cart_items = [
    ['product_id' => 4359],
    ['product_id' => 4320]
];
$cart_product_ids = array_column($cart_items, 'product_id');

echo count(array_intersect($cart_product_ids, $deposit_items ));

Output

2

Sandbox

It can be condensed (Golfed) to a single line like this:

$deposit_items = array( '4359', '4336', '4331', '4320' );
echo count(array_intersect(array_column($cart_object->get_cart(),'product_id'),$deposit_items));

For reference

http://php.net/manual/en/function.array-column.php

http://php.net/manual/en/function.array-intersect.php

Array column, takes that big multi-dimensional array and retruns a single column, using my (somehwhat simple) example:

$cart_items = [
    ['product_id' => 4359],
    ['product_id' => 4320],
    ['product_id' => 333]
];

Becomes (I added 333, just for kicks)

  [4359, 4320, 333]

Basically the same format as your $deposit_items. Once they are the same we can use array intersect, to find all the items in array 1 that appear in the second array. In this case we want the above array items, only if they are in $deposit_items. Once we have those its a simple matter of counting them with count.

Sandbox

Just to illustrate it further

print_r([
    ['product_id' => 4359],
    ['product_id' => 4320],
    ['product_id' => 333]
], 'product_id');

Output

[4359, 4320, 333]

Then

print_r(array_intersect([4359, 4320, 333], ['4359', '4336', '4331', '4320']));

Output

 [4359, 4320]

And then count is pretty strait forward.

Other stuff

Coincidentally if you wanted to do the reverse, count the items NOT in $deposit_items you would simply replace array_intersect with array_diff.

 echo count(array_diff(array_column($cart_items, 'product_id'), $deposit_items ));

Not in Deposit Items

And if you flip the arrays around with array diff, you'd get the number of deposit items NOT in the cart.

 echo count(array_diff($deposit_items, array_column($cart_items, 'product_id')));

Not in cart

Cheers!