How to merge two multidimensional arrays and adjust existing values?

I would like to put together the following arrays and calculate best prices.

$pricesForAllCustomer = array(
    array(
        'from' => '600',
        'to' => 'any',
        'price' => 0.15
    )
);

$customerSpecificPrices = array (
    array(
        'from' => '1',
        'to' => '1799',
        'price' => 0.17
    ),
    array(
        'from' => '1800',
        'to' => 'any',
        'price' => 0.14
    )
);

How can I combine these 2 arrays to achieve the following result?

$calculatedBestOffers = array(
    array(
        'from' => '1',
        'to' => '599',
        'price' => 0.17
    ),
    array(
        'from' => '600',
        'to' => '1799',
        'price' => 0.15
    ),
    array(
        'from' => '1800',
        'to' => 'any',
        'price' => 0.14
    )
);

Can anyone help me?

Answer

One way to do it is to find the element whose from value is greater than pricesForAllCustomer to value and place it between these elements (assuming that customerSpecificPrices is already ordered.):

$pricesForAllCustomer = array(
    array(
        'from' => '600',
        'to' => 'any',
        'price' => 0.15
    )
);

$customerSpecificPrices = array (
    array(
        'from' => '1',
        'to' => '1799',
        'price' => 0.17
    ),
    array(
        'from' => '1800',
        'to' => 'any',
        'price' => 0.14
    )
);

$calculatedBestOffers = [];
$foundPos = false;
foreach($customerSpecificPrices as $key => $elem){
    if(!$foundPos && $pricesForAllCustomer[0]['from'] < $elem['from']){
        $calculatedBestOffers[$key-1]['to'] = $pricesForAllCustomer[0]['from']-1;
        $pricesForAllCustomer[0]['to'] = $elem['from']-1;
        $calculatedBestOffers[] = $pricesForAllCustomer[0];
        $calculatedBestOffers[] = $elem;
        $foundPos = true;
    }
    else $calculatedBestOffers[] = $elem;
}

print_r($calculatedBestOffers);

The result will be:

Array
(
    [0] => Array
        (
            [from] => 1
            [to] => 599
            [price] => 0.17
        )

    [1] => Array
        (
            [from] => 600
            [to] => 1799
            [price] => 0.15
        )

    [2] => Array
        (
            [from] => 1800
            [to] => any
            [price] => 0.14
        )

)