PHP sorting issue with simpleXML

Question

test.xml:

    
        a1

        

Answer 1

My approach was to convert the SimpleXMLElement objects into arrays:

$doc = new SimpleXMLElement($xml);
$states =  get_object_vars($doc->prop->children());
$states = $states["state"];
usort($states, function($t1, $t2) { return strcmp($t1['statename'], $t2['statename']); });
array_walk($states,
    function (&$state) {
        $state = get_object_vars($state);
        array_walk($state["info"],
            function (&$el) {
                $el = get_object_vars($el);
            }
        );
        usort($state["info"],
            function($a, $b) { return strcmp($a["location"], $b["location"]); }
        );
    }
);

Answer 2

You want to sort a list of SimpleXMLElements based on some attribute or element value. You normally do this by turning the list into an array and then apply the sorting on that array.

A function helpful for that in PHP is iterator_to_array. It does the job to turn something that is so magic in simplexml into a more "fixed" array.

Let's say your tour elements in $result->tour. By default simplexml returns an iterator here, something you can not sort out of the box. Let's convert it into an array:

$tours = iterator_to_array($result->tour, false);

Now the $tours variable is an array containing each <tour> element as a SimplXMLElement. You can now sort that array with an array function. Those array sorting functions are outlined in the PHP manual and I normally suggest How do I sort a multidimensional array in php as a good starting point:

$tourDates = array_map(
    function($tour) {return trim($tour->next_bookable_date); },
    $tours
);

// sort $tours array by dates, highest to lowest
$success = array_multisort($tourDates, SORT_DESC, $tours);

And that's already it. The whole code at a glance:

$tours = iterator_to_array($result->tour, false);

$tourDates = array_map(
    function($tour) {return trim($tour->next_bookable_date); },
    $tours
);

// sort $tours array by dates, highest to lowest
$success = array_multisort($tourDates, SORT_DESC, $tours);

foreach ($tours as $tour) {
    ...
}

Answer 3

changing this

foreach ($prop->children() as $stateattr)

to this

foreach ($sortedStates as $stateattr)

did it.

could have sworn I tried that already.