How to add missing elements from from two arrays to first array - php

Question

I am currently using SimpleXML to reading an xml file to generate my first array. This array displays a list of images that are found in a directory and written to xml file.
This has worked for me in the past until I upload new photos to the same album. I like to know what one does to get a complete list of images that got uploaded to the end of that first array. Any suggestions?
XML File:
<album>
<image path="/albums/1/images/100_4124.jpg" />
<image path="/albums/1/images/100_4307.jpg" />
<image path="/albums/1/images/100_4335.jpg" />
</album>
SimpleXML to get array:
$xml = simplexml_load_file('/albums/1/photos.xml');
foreach ($xml->image as $image) {
echo '<li><img src="'.$image.'"></li>';
}
What I am getting for my results:
<li><img src="/albums/1/images/100_4124.jpg"></li>
<li><img src="/albums/1/images/100_4307.jpg"></li>
<li><img src="/albums/1/images/100_4335.jpg"></li>
Scanning the directory for all images:
if ($handle = #opendir('/albums/1/')) {
$filenames = array();
while (false !== ($file = readdir($handle))) {
$ext = substr($file, strrpos($file, '.') + 1);
if ($file != '.' && $file != '..') {
$filenames[] = $file;
$total++;
}
}
}
closedir($handle);
foreach ($filenames as $filename) {
echo '<li><img src="'.$filename.'"></li>';
}
What I would like to get for results using both arrays:
<li><img src="/albums/1/images/100_4124.jpg"></li>
<li><img src="/albums/1/images/100_4307.jpg"></li>
<li><img src="/albums/1/images/100_4335.jpg"></li>
<li><img src="/albums/1/images/100_9000.jpg"></li>
<li><img src="/albums/1/images/100_9001.jpg"></li>
<li><img src="/albums/1/images/100_9002.jpg"></li>
The last 3 images that are missing from xml file would be added it to the end of the list.

Answer 1

Perhaps this would work for you?
<?php
$images = array();
foreach ($xml->image as $image) {
$images[] = $image;
}
foreach (array_diff($filenames, $images) as $image) {
$images[] = $image;
}
foreach ($images as $image) {
echo '<li><img src="' . $image . '" /></li>';
}
?>
This is assuming that $image from the $xml->image and $filename from your dir search are formatted the same. From what you've shown they are. If they aren't should be easy enough to run them through a quick regex to get them in a state where they are comparable.
Any who it looks like array_diff() is what you're looking for.

Answer 2

If you get a full list of the file names in the directory you could use PHP in_array and search for it in an array of your paths
$paths = array();
foreach ($xml->image as $image) {
$paths[] = $image['path'];
}
foreach ($filenames as $filename) {
if (!in_array($filename, $paths) {
$newImage = $xml->addChild('image');
$newImage->addAttribute('path', $filename);
}
}
// save adjusted xml file, assuming you have permission
$xml->asXML('/albums/1/photos.xml');
foreach ($xml->image as $image) {
echo '<li><img src="'.$image.'"></li>';
}