php - Collating multidimensional array values

Question

I have a multidimensional array in the form of;

Array
(
    [0] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Bob Hope
            [ITEM] => Holiday
            [DURATION] => 04:00
        )
    [1] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Bob Hope
            [ITEM] => Work
            [DURATION] => 05:00
        )
    [2] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Bob Hope
            [ITEM] => Holiday
            [DURATION] => 06:00
        )
    [3] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Bob Hope
            [ITEM] => Work
            [DURATION] => 05:00
        )
    [4] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Joe Bloggs
            [ITEM] => Holiday
            [DURATION] => 02:00
        )
    [5] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Joe Bloggs
            [ITEM] => Work
            [DURATION] => 03:00
        )
    [6] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Joe Bloggs
            [ITEM] => Holiday
            [DURATION] => 03:00
        )
    [7] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Joe Bloggs
            [ITEM] => Work
            [DURATION] => 02:00
        )
)

And want to collate the results, totalling the holiday and work for each person so that I can output something in the form of;

Array
(
    [0] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Bob Hope
            [ITEM] => Holiday
            [DURATION] => 10:00
        )
    [1] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Bob Hope
            [ITEM] => Work
            [DURATION] => 10:00
        )
    [2] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Joe Bloggs
            [ITEM] => Holiday
            [DURATION] => 05:00
        )
    [3] => Array
        (
            [DATE] => 05-19-2011
            [PERSON] => Joe Bloggs
            [ITEM] => Work
            [DURATION] => 05:00
        )
)

Any ideas? Any and all help appreciated.

Answer 1

Where's the data coming from? Generally, such data comes from a database, in which case the following statement would do exactly what you want:

SELECT 
   SUM(DURATION),
   ITEM,
   PERSON
FROM
   yourtable
GROUP BY 
   PERSON, 
   ITEM;

Edit: If you want to group them by items too, just declare that.