Question

Lets say I’ve got an array:

Array
(
    [0] => Array
        (
            [filmType] =>  Symphony 15%
            [rollSize] => 36
            [linearFt] => 3
        )

    [1] => Array
        (
            [filmType] =>  Symphony 15%
            [rollSize] => 36
            [linearFt] => 3
        )
    [2] => Array
        (
            [filmType] =>  Symphony 15%
            [rollSize] => 48
            [linearFt] => 5
        )

    [3] => Array
        (
            [filmType] =>  Symphony 25%
            [rollSize] => 36
            [linearFt] => 7
        )
    [4] => Array
        (
            [filmType] =>  Symphony 35%
            [rollSize] => 36
            [linearFt] => 10
        )
    [5] => Array
        (
            [filmType] =>  Symphony 35%
            [rollSize] => 36
            [linearFt] => 10
        )

How is it possible to add up the [linearFt] of ONLY unique array elements. By unique I mean [filmtype] and [rollSize] the same.

I have tried multible ways including searching array, array filter, and usort… I am new to PHP and this is NOT homework. Thanks for any help!

So my output would be:

$totalsArray = Array(

    [0] => Array
        (
            [filmType] =>  Symphony 15%
            [rollSize] => 36
            [linearFt] => 8
        )

    [1] => Array
        (
            [filmType] =>  Symphony 15%
            [rollSize] => 48
            [linearFt] => 3
        )
    [2] => Array
        (
            [filmType] =>  Symphony 25%
            [rollSize] => 48
            [linearFt] => 7
        )
    [3] => Array
        (
            [filmType] =>  Symphony 35%
            [rollSize] => 48
            [linearFt] => 20
        )

Answer 1

Ah. I would attack this with a foreach loop to get each array, then accumulate the different types and sizes and add them as I go. It would look like this:

$filmTotals = array();
$filmTemp   = array();
foreach ($filmInventory as $film){
    $filmTemp[$film['filmType']][$film['rollSize']] = $filmTemp[$film['filmType']][$film['rollSize']] + $film['linearFt'];
}

// A second foreach to resort into the final format, nested to get the keys out to rename them correctly
foreach ($filmTemp as $filmType=>$film){
    foreach ($film as $filmSize=>$filmLength){
        $filmTotals[] = array('filmType'=>$filmType, 'rollSize'=>$filmSize, 'linearFt'=>$filmLength);
    } //END inner foreach
} // END outer foreach