PHP simplexml reverse

Question

Is there any way to loop through an xml loaded in simpleXML in reverse? say if i have the following xml

$string ="<items>
    <item>1</item>
    <item>2</item>
    <item>3</item> 
</items>";

$xml = simplexml_load_string($string);

is there any way to reverse $xml so that i get item 3 when i do a foreach

Answer 1

$xml->item is an array. Use array sorting functions.

rsort($xml->item);
print_r($xml->item);

EDIT: Ok, there is no way to do this. You have to make an array first.

$myArray = array_reverse((array)$xml->item, true);
print_r($myArray);

(no testing again)

Answer 2

Since Iterators in PHP have no previous style method, the short answer is no. You could read them into an array and then reverse the array, but that wouldn't be directly iterating backwards.

One option would be to create a ReverseIterator, where you wrap a regular iterator and then traverse it backwards. But that might get problematic since you don't know if a iterator has an end (You can see some examples that don't in the SPL).

So no, you can't. Your only option would be to do something like this:

$nodes = array();
foreach ($xml AS $node) {
    array_unshift($nodes, $node);
}

Answer 3

$items = $xml->item;
for ($i = count($items) - 1; $i >= 0; $i--)
{
    echo (string) $items[$i].", ";
}

Answer 4

With simplexml:

<?php
$string ="<items>
    <item>1</item>
    <item>2</item>
    <item>3</item>
</items>";

$xml = simplexml_load_string($string);

$length = count($xml->item);
for($i = $length; $i; --$i) {
    echo $xml->item[$i-1];
}

prints:

321

Another expample:

It's a little verbose and it uses the more powerful DomDocument and not SimpleXml if you really want to ;)

<?php
$string ="<items>
    <item>1</item>
    <item>2</item>
    <item>3</item>
</items>";

$oXml = DomDocument::loadXml($string);

$oItems = $oXml->firstChild->childNodes;
$lastItemIndex = $oItems->length;

$oItem = $oItems->item($lastItemIndex-1);
do {
    echo $oItem->nodeValue;
} while($oItem = $oItem->previousSibling);

prints:

3
2
1

Answer 5

Assuming the OP is a beginner only interested in a solution I'd recommend using xpath() to get the elements and array_reverse() to reverse their order:

$items = array_reverse($xml->xpath('item'));

Note: the XPath "item" grabs all <item/> elements that are the direct children of current element.