php - array_sum() to values within an array -

how can add array_sum string in loop without making foreach loop it? trying combine of numbers instead of having multi dimensional array , have value , see array_sum wont add them because inside of array. ideas?

$hours_arr = array(); foreach($proj_time $item){     $hours_arr [$item['project_id']]['item_value'] = $item['item_value'];     $hours_arr [$item['project_id']]['hours'][] = $item['hours']; }  //output array (size=3)   4 =>      array (size=2)       'item_value' => string 'coaching' (length=8)       'hours' =>          array (size=1)           0 => string '999.99' (length=6)   1487 =>      array (size=2)       'item_value' => string 'standby' (length=7)       'hours' =>          array (size=1)           0 => string '15.00' (length=5)   1488 =>      array (size=2)       'item_value' => string 'standby' (length=7)       'hours' =>          array (size=4)           0 => string '10.00' (length=5)           1 => string '10.00' (length=5)           2 => string '10.00' (length=5)           3 => string '10.00' (length=5) 

i output be

1488 =>      array (size=2)       'item_value' => string 'standby' (length=7)       'hours' => string '40.00' (length=5) 

edit: added contents of $proj_time

array (     [0] => array         (             [project_id] => 4             [consultant_id] => 51             [engagement_id] => 8             [hours] => 999.99             [item_value] => coaching         )      [1] => array         (             [project_id] => 1487             [consultant_id] => 1             [engagement_id] => 1             [hours] => 15.00             [item_value] => standby         )      [2] => array         (             [project_id] => 1488             [consultant_id] => 31             [engagement_id] => 7             [hours] => 10.00             [item_value] => design app rfp         )      [3] => array         (             [project_id] => 1488             [consultant_id] => 32             [engagement_id] => 41             [hours] => 10.00             [item_value] => training         )      [4] => array         (             [project_id] => 1488             [consultant_id] => 55             [engagement_id] => 41             [hours] => 10.00             [item_value] => training         )      [5] => array         (             [project_id] => 1488             [consultant_id] => 1             [engagement_id] => 1             [hours] => 10.00             [item_value] => standby         )  ) 

instead of creating array , applying operation, while creating why don't sum this:

demo

$hours_arr = array(); foreach($proj_time $item){     $hours_arr [$item['project_id']]['item_value'] = $item['item_value'];     if(array_key_exists('hours', $hours_arr [$item['project_id']]))         $hours_arr [$item['project_id']]['hours'] += $item['hours'];     else         $hours_arr [$item['project_id']]['hours'] = $item['hours'];  } 

result:

array (     [4] => array         (             [item_value] => coaching             [hours] => 999.99         )      [1487] => array         (             [item_value] => standby             [hours] => 15         )      [1488] => array         (             [item_value] => standby             [hours] => 40         )  )