Question

I have a multi dimensional array with some data.

    Array  ID      Date     Quantity
    66998  [0] [2011-05-11] [50]
           [1] [2011-05-15] [50]
           [2] [2011-05-15] [50]
    81158  [0] [2011-05-11] [25]
           [1] [2011-05-12] [60]
           [2] [2011-05-16] [60]
           [3] [2011-05-18] [60]

I would like to add up all the Quantities from orders within same week. I can calculate the week number with:

            $WeekNumber = date("W", $UnixTimestamp);

So the final array should look like this:

               Week Quantity
    66998  [0] [19] [150]
    81158  [0] [19] [85]
           [1] [20] [120]    

The array is generated from MS SQL database.

Answer 1

You could use array_reduce($array, 'function_name') to produce the result array one step at a time.

function calc_weeks($result, $row)
{
    . . .
    $WeekNumber = date("W", $UnixTimestamp);
    $result[$weekNumber] += $row['quantity'];
    return $result;
}
array_reduce($array, 'calc_weeks', array());

Alternatively you could use SQL to calculate week numbers and sum your orders that way. In MySQL the function is called WEEK(). For MS SQL there’s a related question here.