从中的关联数组中获得最大值，如果相等，则以其他值最低获得最高值

Question

Let me try and explain this as easy as possible. I have an array which contains the shipping fees of several products.

I have the value of

Item ID Local Shipping International Shipping Additional Local Shipping Additional International Shipping

To make it easier, I just need to know how to calculate the part of the local shipping. I can afterwards apply the same formula to the international shipping part.

The array may contain 1 or 5 or 100 products, each with their own different (or same) amounts, like this:

Array ( 

    [0] => Array ( 
        [item_id] => 788 
        [local_shipping] => 13.00 
        [intl_shipping] => 45.00 
        [addl_local_shipping] => 10.00 
        [addl_intl_shipping] => 20.00 
    )
    [1] => Array ( 
        [item_id] => 234 
        [local_shipping] => 23.00 
        [intl_shipping] => 5.00 
        [addl_local_shipping] => 1.00 
        [addl_intl_shipping] => 2.00 
    )
    [2] => Array ( 
        [item_id] => 543 
        [local_shipping] => 23.00 
        [intl_shipping] => 6.00 
        [addl_local_shipping] => 0.50 
        [addl_intl_shipping] => 5.00 
    )

) 

So, what I'm trying to get is the array that contains the HIGHEST local_shipping value, which in that case would be both [1] and [2] with "23.00".

If there's only one unique highest value, I need it to return the "local_shipping" and the "addl_local_shipping" like

Local Shipping is 23.00 and additional local shipping is 1.00

Now, if there's 2 arrays with common highest values, I need it to return the one with the LOWEST "addl_local_shipping" value, which in that case is [2] like:

Local Shipping is 23.00 and additional local shipping is 0.50

Does that make sense?

I was able to get the highest "local_shipping" value out of the array with this:

$max = 0;
foreach( $my_array as $k => $v )
{
$max = max( array( $max, $v['local_shipping'] ) );
}
echo "Local Shipping is " . $max;

But I have no idea how to figure out how to print the related "addl_local_shipping" string AND sort out the problem if there are multiple ones with an equal high value.

Answer 1

You can use usort to sort the array based on local shipping descending and additional ascending, then take the values from the 1st result in the array:

usort($array, function($a, $b){
    return $b['local_shipping'] - $a['local_shipping'] ?:
        $a['addl_local_shipping'] - $b['addl_local_shipping'];
});

echo 'local shipping: ' . $array[0]['local_shipping'];
echo 'additional local shipping: ' . $array[0]['addl_local_shipping'];

However, as noted in comments, if you are getting this data from an sql query, it makes more sense to let the database do the work for you with an ORDER BY clause. The result will be the same - the 1st element in the array will have the data you require