Recursive Function

[Electric_Studio]

I am trying to create a sitemap of my site using PHP. I have an array contain all my site's page data stored as $sitemap. For instance here are some test echoes:

echo $sitemap[0][1]->title; // 'Home'
echo $sitemap[0][1]->title; // 'Who We Are'

Now to create my sitemap I need a recursive function to iterate through the array and show all my pages. I tried working through some examples to do this, but it is not working, it currently only echoes the first level of pages. Can anyone help?

function print_recurse(&$array){
	foreach ($array as $element) {
        if(is_array($element)) {
            print_recurse($element);
        } else {
            echo $element->title . "<br/>";
        }
    } 
}

print_recurse($sitemap);

/* Produces:
Home
Who We Are
What We Do
Our Work
News
Contact */

[laserlight]

At a glance, that function looks like it should work. Are you sure the array was created as you expected it to be? Do a print_r($sitemap) to check.

[Electric_Studio]

After further investigation using print_r($sitemap) I find that my array contains objects. I understand how arrays work but I don't understand objects so I would be grateful if you could help me modify my function to iterate through the objects in my array. Here is a sample from print_r($sitemap) of a node which has a 'title' key (value = 'Website Design') I wish to print out:

[children] => Array
                                                (
                                                    [0] => HierarchyElementModel Object
                                                        (
                                                            [nodetype] => page-content
                                                            [nodeid] => website-design
                                                            [parent] => HierarchyElementModel Object
 *RECURSION*
                                                            [title] => Website Design
                                                            [navigation] => Array
                                                                (
                                                                    [showinmenu] => show
                                                                    [menutitle] => Website Design
                                                                    [code] => 
                                                                    [summary] => 
                                                                    [titletag] => 
                                                                )

                                                        [created] => 2008-08-19 15:53:15
                                                        [modified] => 2008-08-19 15:53:15
                                                        [children] => Array
                                                            (
                                                            )

                                                        [permissions] => IndependentPermissionsModel Object
                                                            (
                                                                [number:private] => 2
                                                            )

                                                    )

[Ashley_Sheridan]

I had a similar problem when I was using SimpleXML, as it was returning objects. The print statements were correctly converting the objects to strings, but when I was trying to use them for something else, they weren't converted. In the end I resorted to using settype() on the objects to convert copies of them to strings, which I could then use as I wanted.

[Electric_Studio]

Here is my recursive function as it stands; it currently doesn't work because I have tried to convert the objects to arrays as you suggested, but of course they are only converted in that instance of the 'foreach' function, i.e. the array data is not actually being modified, so I get a "Warning: Invalid argument supplied for foreach() " appear.

I would be very grateful if anyone could help me with this, as I am pulling my hair out trying to get it to work!!

function print_recurse(&$array){
	foreach ($array as $element) {

	if (is_object($element)){
		$element = settype($element, "array");
		print_recurse($element);
	}

    if(is_array($element)) {
		print_recurse($element);
    } elseif (!is_object($element)){
		echo "<li><a href=\"" . URIComponent::publicURL($element['nodeid']) . "\">" . $element['title'] . "</a></li>";
	}

} 
}

echo "<ul>";
print_recurse($sitemap);
echo "</ul>";

[Electric_Studio]

Thinking about it, I am sure I am over complicating things. This function nearly works, and just needs a little tweaking:

function print_recurse(&$array){
	foreach ($array as $element) {

	if(is_array($element)){
		// If there are more levels to recurse
		print_recurse($element);
	} else {
		// Element has no children, so no more levels to recurse
		echo "<li><a href=\"" . URIComponent::publicURL($element->nodeid) . "\">" . $element->title . "</a></li>";
	}

} 
}

It needs to iterate through objects too. So if I change the line:

if(is_array($element)){

To:

if(is_array($element) || is_object($element)){

It crashes my local Apache server, presumably because it recurses infinitely. So I need another part of the IF statement, to say IF is an array OR is an object AND the object has children.

The part I can't figure out, how do I test whether an object has children?!

[Weedpacket]

I'm going to guess "(is_object($element) && !empty($element->children))"

[Electric_Studio]

Thanks for that Weedpacket, I think we are getting somewhere now.

My local Apache server still crashes when I run the function, but I have added a limit to my function, so it now looks like this:

$i = 0;

function print_recurse(&$array){
	foreach ($array as $element) {

	if($i < 7){
		if(is_array($element) || (is_object($element) && !empty($element->children))){
			// If there are more levels to recurse
			print_recurse($element);
		} else {
			// Element has no children, so no more levels to recurse
			echo "<li><a href=\"" . URIComponent::publicURL($element->nodeid) . "\">" . $element->title . "</a></li>";
		}
		$i++;

	}

} 
}

When I limit my function to 7 elements, it doesn't crash my server. When I set it to 8 elements, it crashes it. So I have narrowed the problem down to this particular element:

[permissions] => IndependentPermissionsModel Object
                                                                                        (
                                                                                            [number:private] => 2
                                                                                        )

There are two interesting things about this object:
- It is the first object in the array to have a private property
- It is the first object in the array to have no children

Which one of these things could be causing my function to fail, and how can I work around it?