Q:

How to sort an array by values in another array in PHP

I have an array of image URLs saved from a form submission. I then give users the ability to edit the form values and sort their images using .sortable from jQueryUI. I take the sorted ID's and add them to a hidden input which adds them to the main POST data and into the saved array of form values. 
Saved Form Data:
$dataArray(
   [firstName] => Alex
   [lastName] => Ander The Great
   [imageorder] => image1,image3,image2,image4
)

$filesArray(
   [image1] => url.png
   [image2] => url2.png
   [image3] => url3.png
   [image4] => url4.png
)

$imageorder = explode(',', $dataArray['imageorder']);
/* Gives the following */
array(
   [0] => image1
   [1] => image3
   [2] => image2
   [3] => image4
)

What I need to do is to be able to get the following to order by the $imageorder var.
<?php foreach($filesArray as $image) { ?>
  <img src="<?php /*echo the correct image url*/ ?>">
<?php } ?>

A:

You can achieve that by modifying the foreach loop as: 
<?php foreach($imageorder as $image) { ?>
  <img src="<?php echo $filesArray[$image] ?>">
<?php } ?>

So basically loop on the order array but echo from the original array

