替换性地替换数组的元素

Question

I need to create an array of prices. So I've an array of base prices and an array of promotional prices, if the promotional price is lower than the base price, I put it in the new array of prices. For this purpose I wrote this code:

<?php 
    $array_base_prices = array(
        array('id'=>1, 'price'=>10),
        array('id'=>2, 'price'=>2),
        array('id'=>3, 'price'=>30),
        array('id'=>4, 'price'=>40)
     );

     $array_promo = array(
        array('id'=>1, 'price'=>20),
        array('id'=>2, 'price'=>5),
        array('id'=>3, 'price'=>2)
     );

     $base_prices_with_promo = array();

     foreach ( $array_base_prices as $j => $u ) {

        foreach ( $array_promo as $k => $v ) {

           if ( ($v['id'] == $u['id']) && $u['price'] < $v['price']) {

                $base_prices_with_promo[$j]['id'] = $array_base_prices[$j]['id'];
                $base_prices_with_promo[$j]['price'] = $array_base_prices[$j]['price'];

           }

           if ( ($v['id'] == $u['id']) && $u['price'] > $v['price']) {

                $base_prices_with_promo[$j]['id'] = $array_promo[$k]['id'];
                $base_prices_with_promo[$j]['price'] = $array_promo[$k]['price'];            

           }

        }

    }

    $base_prices_with_promo = array_replace( $array_base_prices, $base_prices_with_promo );

    echo "<pre>";
    print_r($base_prices_with_promo);
    echo "</pre>";

?>

and it works fine, but I think that the if conditions into the nested foreach are a little messy. I'm working with multidimensional, associative arrays, very big with a lot of keys. So I'm wondering if there is any better alternative to achieve the same result.

Answer 1

There's really not enough context for me to be sure that this is an option for you, but from your little example I would change the array declaration to this:

$array_base_prices = array(
    1 => 10,
    2 => 2,
    3 => 30,
    4 => 40
);

$array_promo = array(
    1 => 20,
    2 => 5,
    3 => 2
);

Or use an array if you need to store more data than just price:

$array_base_prices = array(
    1 => array("price" => 10, "something_else" => null)
);

The point is to have the id as index of the parent array. Then your nested loops turn to this:

foreach ($array_base_prices as $id => $base_price) {
    $base_prices_with_promo[$id] = $base_price;
    if (isset($array_promo[$id]) && $base_price > $array_promo[$id]) {
        $base_prices_with_promo[$id] = $array_promo[$id];
    }
}