Round a PHP 2d Array by a Specified Key

Round a specified key of a 2-dimentional PHP array. The first parameter is specified as a reference. This causes any changes, ie, the rounding function to effect the original array elements; array_walk_recursive() operates on all items in an array by a specified function.

array_walk_recursive($array, 'round2dArrayByKey');

function round2dArrayByKey(&$item)  {
    $n = 2; // set this to the rounding accuracy required
    $item = round($item, $n);
}

Example:

PHP Array:
$array = array (
    array(Classic Collections,"Abilene, TX 79602",2.71828​,"red"),
    array(Fabulous Finds,"Abilene, TX 79601",3.14159​,"blue"),
    array(Honeycomb Tree,"Abilene, TX 79601",1.41421​,"green")
);

PHP: 
array_walk_recursive($array, 'round2dArrayByKey');

function round2dArrayByKey(&$item)  {
    $item = round($item, 2);
}

Produces this result:

Array
(
    [0] => Array
        (
            [0] => Classic Collections
            [1] => Abilene, TX 79602
            [2] => 2.72
            [3] => https://www.facebook.com/Classic-Collections
        )

    [1] => Array
        (
            [0] => Fabulous Finds
            [1] => Abilene, TX 79601
            [2] => 3.14
            [3] => http://www.fabulousfinds.com/
        )

    [2] => Array
        (
            [0] => Honeycomb Tree
            [1] => Abilene, TX 79601
            [2] => 1.41
            [3] => https://www.facebook.com/The-Honeycomb-Tree/
        )

)