Question

I have two arrays I need to compare….

$Drink Array

(
[0] => Drink Object
    (
        [top_id] => 40C6-88
        [name] => Pepsi
        [drink_id] => E936
    )

[1] => Drink Object
    (
        [top_id] => 46DB-9E
        [name] => Orange Juice
        [drink_id] => E936
    )
)

[2] => Drink Object
    (
        [top_id] => 5J71-4F79
        [name] => Dr Pepper     
        [drink_id] => E936
    )

$DrinkItem Array

(
[0] => DrinkItem Object
    (
        [bottom_id] => 45BD-92DD
        [name] => Diet Coke      
        [drink_template_id] => 3B2A-4D82
    )

[1] => DrinkItem Object
    (
        [bottom_id] => 4A71-8F79
        [name] => Orange Juice     
        [drink_template_id] => 3B2A-4D82
    )


)

.. If the name matches one of the names in the DrinkItem Array I need to store the top_id of that item.

I was trying to do something like:

foreach ($Drink as $d) {
    foreach ($DrinkItem as $item){
        if ($d->name == $item->name){
            $match = $d->top_id;
        }
    }
}

But I might be way off base here. If there’s a better approach for storing the id of the matches, or if i’m on the right track, any help is very appreciated!

Answer 1

You might be better off creating an index first:

$drinkindex = array();

// Note that names need to be unique.
foreach ($Drink as $d) {
    $drinkindex[$d->name] = $d->top_id;
}

$matches = array();
foreach ($DrinkItem as $di) {
    $match = $drinkindex[$di->name];
    if ($match!==NULL) {
        $matches[$match] = True;
    }
}

// $matches is a set of top_id.
// If you may have duplicates and you want those represented, use a list instead.

If you need the entire Drink object and not just the top_id, consider using array intersection, like so:

function namecompare($a, $b) {
    if ($a->name === $b->name) {
        return 0;
    } else {
        return ($a->name < $b->name) ? -1: 1;
    }
}

$intersection = array_uintersect($Drink, $Drinkitem, 'namecompare');

var_dump($intersection); // contains $Drink[1];