PHP - array_map 2 columns and remove duplicate rows by key

Question

I have the following array dynamically generated from an external API:

$purchases = array(
    array('product_id' => 7, 'receipt' => R13D13),
    array('product_id' => 5, 'receipt' => Y28Z14),
    array('product_id' => 7, 'receipt' => R02310),
    array('product_id' => 5, 'receipt' => E11403)
);

Desired output:

$purchases_new = array(
    array('product_id' => 7, 'receipt' => R13D13),
    array('product_id' => 5, 'receipt' => Y28Z14)
);

Due to the nature of the API I have only been able to pull data using array_map:

$purchases_unique = array_unique(
    array_map(function($pid){ return $pid['product_id']; }, $purchases)
);
print_r($purchases_unique);

Outputs

array((array[251] => 7) array([252] => 5))

Output completely not what I want :( How to array_map 2 columns product_id' and receipt and remove duplicate rows based on product_id?

I want to achieve the following:

1. array_map both columns? (product_id and receipt)
2. Remove product_id duplicates rows based on product_id key?

Answer 1

If you want the first occurrence use @TheFirstBird answer. If you want the last occurrence you can do it simpler buy using array_column and array_values as:

$newArr = array_values(array_column($purchases, null, "product_id")); 

Notice the second argument of array_column is null meaning take the entire element.

Live example: 3v4l

References: array-column, array-values