比较多维数组中的元素

I have a multidimensional array where one of the elements looks like the following:

Array
(
[9-0048-1:G07] => Array
    (
        [wafer] => 9-0048-1
        [cell] => G07
        [isc] => 2.922336
        [start_time] => 2014-07-21 09:51:56
    )

I set the key of each element equal to the wafer and cell. Each wafer has 5 different types of cells. I want to compare the 5 different cells in each wafer and do some calculations. The 5 different type of cells are C09, c05, K05, K09, and G07. I want to be able to do calculations with the ISC of each cell. Such as I want to compare the ISC of two cells (c09 and c05) and find the uniformity ((bigger value - lower value)/bigger value) of the two. I'm not sure how to go about being able to compare the different values.

This code may help you, let's say your multidimensional array is $Array and you need to compare elements with wafer="9-0048-1", then this code will help you get all the elements with the wafer="9-0048-1" in an array

$wafer_to_compare = "9-0048-1";
    $array_to_compare = [];
    foreach ($Array as $key => $array) 
        if(strpos($key, $wafer_to_compare)!=null)
            $array_to_compare[] = $array;