How to read child of interleaved XML in PHP - php

Question

We need to update a somewhat old API a customer is using. We're getting the data with simplexml_load_file. The new structure is a bit more complex and I could not find a way to retrieve the new data.
The new structure looks like this:
Before we used $ratingPrice = $xml->hotel->ratingPrice; to get a value.
Now, I need to retrieve $xml->business->subcategoryRating->subcategoryRating->averageRating. I'm now stuck with that.
How am I able to get the average rating of wifi, or location and have them outputted in single variables?

Answer 1

If the order of your information is always the same (eg. Wi-Fi, Location, Apartment, Cleanliness) then you can do
$xml->business->subcategoryRating->subcategoryRating[x]->averageRating
so the x is the index of your xml list. Then
...subcategoryRating[0]->averageRating
corresponds to Wi-Fi and
...subcategoryRating[1]->averageRating
corresponds to Location and so forth.

Answer 2

You can extract the various ratings into an array and then use the relevant index to process the data your after. This uses the id attribute of the (for example) <category id="location"> element to use as the index...
$ratings = [];
foreach ( $xml->business->subcategoryRatings->subcategoryRating as $rating ) {
$ratings[(string)$rating->category['id']] = (string)$rating->averageRating;
}
echo $ratings["location"].PHP_EOL;
This last line will need to be updated to access the particular element your after.

Answer 3

As an alternative you could create an xpath expression and use xpath.
That would give you array of SimpleXMLElement objects.
$xml = simplexml_load_string($data);
$expression = '//business/subcategoryRatings/subcategoryRating[category[#id="wifi" or #id="location"]]';
foreach($xml->xpath($expression) as $item) {
$averageRating = (string)$item->averageRating;
}