I need to replace all the total values with the corresponding subtraction of start and end values. Values are come from a sql result
Any help how to do that?
For Ex :

12.30 - 5.00 = 7.30

15.30 - 7.00 = 8.30

16.30 - 9.00 = 7.30

Existing array

```
array(184) {
   [1]=>
      array(3) {
         ["start"]=>
         string(4) "5.00"
         ["end"]=>
         string(4) "12.30"
         ["total"]=>
         string(4) "1.00"
      }
   [2]=>
      array(3) {
         ["start"]=>
         string(4) "7.00"
         ["end"]=>
         string(4) "15.30"
         ["total"]=>
         string(4) "1.00"
      }
   [3]=>
      array(3) {
         ["start"]=>
         string(4) "9.00"
         ["end"]=>
         string(4) "16.30"
         ["total"]=>
         string(4) "1.00"
      }
    ... // more records are there
 }

```

Replaced final array

```
 array(184) {
    [1]=>
       array(3) {
        ["start"]=>
        string(4) "5.00"
        ["end"]=>
        string(4) "12.30"
        ["total"]=>
        string(4) "7.30"
    }
    [2]=>
      array(3) {
        ["start"]=>
        string(4) "7.00"
        ["end"]=>
        string(4) "15.30"
        ["total"]=>
        string(4) "8.30"
   }
   [3]=>
     array(3) {
       ["start"]=>
       string(4) "9.00"
       ["end"]=>
       string(4) "16.30"
       ["total"]=>
       string(4) "7.30"
   }
... // more records are there
 }

```