Remove XML Node if Child Node equals to an array value - php

Question

I'm trying to remove "Product" nodes from an XML if "ProductID" is one of the values in an array. For some reasons, my code only removes the "Product" node with the first "ProductID" found in the array. How do I remove all "Product" nodes if their "ProductID" is one of the values in the array? Are there better way to code this?
Example of the XML:
<Product>
<ProductID>ZZ-DS</ProductID>
<Item>Drop Ship Charges</Item>
<Qty>578</Qty>
<ListPrice>2.50</ListPrice>
<YourPrice>2.50</YourPrice>
<UPC/>
<VendorProductID/>
<ImageSmall>URL</ImageSmall>
<ImageLarge>URL</ImageLarge>
</Product>
<Product>
<ProductID>ZZAI-100</ProductID>
<Item>ZZAI-100</Item>
<Qty>0</Qty>
<ListPrice>0.75</ListPrice>
<YourPrice>0.75</YourPrice>
<UPC/>
<VendorProductID>AI- BUBBLES</VendorProductID>
<ImageSmall>URL</ImageSmall>
<ImageLarge>URL</ImageLarge>
</Product>
What I did:
foreach($xml->Product as $product) {
// Not allowed product IDs
$notAllowed = array('ZZ-DS','ZZAI-100','ZZAI-101','ZZAI-TG01','ZZWM-BL00001N','ZZWM-BL00176N','ZZWM-DJ00089N','ZZWM-DL00195N','ZZWM-DL00196N','ZZWM-DL00198N','ZZWM-DL00292N','ZZWM-DL00293N','ZZWM-DL00295N','ZZWM-UG00049N','ZZWM-UG00050N','ZZWM-UG00051N','ZZWM-V012194N','ZZWM-V012197N','ZZWM-V012207N','ZZWM-V012216N','ZZWM-V021012N','ZZWM-WM10086N','ZZWM-WMP0037N');
if (in_array($product->ProductID, $notAllowed)) {
$deleteNode = dom_import_simplexml($product);
$deleteNode->parentNode->removeChild($deleteNode);
}
}
As the result, the code removed only "Product" node with "ProductID" equals to "ZZ-DS".

Answer 1

The issue is a case of trying to loop over the contents of an array and then removing parts of that array, the array becomes out of sync with the loop. You can see this if you add echo $product->ProductID.PHP_EOL; to the loop and see what gets displayed.
Here are two ways to solve this. The first just uses XPath to find a list of the nodes to work with and then loop over these nodes and check the ID and remove if you want. As your looping over the XPath list of nodes, it will not change whilst removing the nodes your after...
$products = $xml->xpath("//Product");
foreach($products as $product) {
if (in_array($product->ProductID, $notAllowed)) {
$deleteNode = dom_import_simplexml($product);
$deleteNode->parentNode->removeChild($deleteNode);
}
}
The second method would be to select just the nodes you want to delete, this involves building an XPath expression something like...
//Product[ProductID='ZZ-DS' or ProductID='ZZAI-100' or ...]
So this is just a case of imploding the list of ID's with the appropriate other bits, then it's a case of removing all the matching nodes...
$notAllowedList = implode("' or ProductID='", $notAllowed);
$products = $xml->xpath("//Product[ProductID='".$notAllowedList."']");
foreach($products as $product) {
$deleteNode = dom_import_simplexml($product);
$deleteNode->parentNode->removeChild($deleteNode);
}