Check first element in each array before moving onto the second - php

Question

I'm trying to do something to each "Order1" in the array before moving on to "Order2". Is there a way to do this in PHP?
Note: It's not always going to be called "Order1". I'm just using this as a generic term right now. Will most likely be an order#
Here's the original array:
Array
(
[100 Series] => Array
(
[Order1] => 4
[Order2] => 4
[Order3] => 4
[Order4] => 4
)
[50 Series] => Array
(
[Order1] => 4
[Order2] => 4
[Order3] => 4
[Order4] => 4
)
)
And here's what it should look like after going through once:
Array
(
[100 Series] => Array
(
[Order1] => 0
[Order2] => 4
[Order3] => 4
[Order4] => 4
)
[50 Series] => Array
(
[Order1] => 0
[Order2] => 4
[Order3] => 4
[Order4] => 4
)
)
Here's some logic added.. it's using some other array data not mentioned.
foreach($orders[$project] as $order => $hoursA)
{
if(array_key_exists($project, $orders) && !empty($orders[$project]))
{
if($resources[$name]["Schedule"][$day] >= $hoursA && $resources[$name]["Schedule"][$day] != 0)
{
$workFlow[$day][$project][$order][$name] = $hoursA;
$resources[$name]["Schedule"][$day] = (($resources[$name]["Schedule"][$day] - $hoursA < 0.000000001) ? 0 : $resources[$name]["Schedule"][$day] - $hoursA);
$orders[$project][$order] = 0;
} else if($resources[$name]["Schedule"][$day] < $hoursA)
{
$workFlow[$day][$project][$order][$name] = $resources[$name]["Schedule"][$day];
$orders[$project][$order] = $orders[$project][$order] - $resources[$name]["Schedule"][$day];
$resources[$name]["Schedule"][$day] = $resources[$name]["Schedule"][$day] - $resources[$name]["Schedule"][$day];
}
}
}

Answer 1

$searchFlag = 'Order1';
foreach($arrays as $array)
{
foreach($array as $key => $val)
{
if($key == $searchFlag) {
//do something to make 0
$arrays[$array][$key] = 0;
}
}
}

Answer 2

If it's always a specific key that you need setting to zero:
array_walk_recursive(
$data,
function(&$value, $key) {
if ($key == 'Order1') $value = 0;
}
);

Answer 3

Something like this:
foreach ($arr as $key => &$value) {
$_key = array_search(reset($value), $value);
$value[$_key] = 0;
}

Answer 4

Building off of Mark Baker's solution -- but making it more applicable for any number of arbitrary key names:
function setOrderToZeroForKey( $orderKey ) {
array_walk_recursive( $data, function( &$value, $key ) {
if( $key === $orderKey ) $value = 0;
}
}
array_walk( array( 'Order1', 'Order2', 'Order3', 'Order4' ), setOrderToZeroForKey );
(may not scale well -- if not, consider a more efficient data structure)