SimpleXML load String将值放入PHP中的Array（）中

I have a XML in form of String (after XLS transform):

<course>
    <topic>
        <chapter>Some value</chapter>
        <title>Some value</title>
        <content>Some value</content>
    </topic>
    <topic>
        <chapter>Some value</chapter>
        <title>Some value</title>
        <content>Some value</content>
    </topic>
    ....
</course>

Then I'm pushing above mentioned XML into the Array():

$new_xml = $proc->transformToXML($xml);

$xml2 = simplexml_load_string($new_xml);
$root = $xml2->xpath("//topic");

$current = 0;
$topics_list = array();

// put the xml values into multidimensional array
foreach($root as $data) {
    if ($data === 'chapter') {
        $topics_list[$current]['chapter'] = $data->chapter;
    }
    if ($data === 'title') {
        $topics_list[$current]['title'] = $data->title;
    }
    if ($data === 'content') {
        $topics_list[$current]['content'] = $data->content;
    }
    $current++;
}
print_r($topics_list);

Problem: Result is empty array. I've tried string like:

$topics_list[$current]['chapter'] = (string) $data->chapter;

but result is still empty. Can anyone explain, where is my mistake. Thanks.

Because my topic element has only simple child elements and not attributes, I can cast it to array and add it to the list (Demo):

$xml2 = SimpleXMLElement($new_xml);
$topics_list = array();
foreach ($xml2->children() as $data) {
    $topics_list[] = (array) $data;
}

The alternative method is to map get_object_vars on the topic elements (Demo):

$topics_list = array_map('get_object_vars', iterator_to_array($xml2->topic, false));

But that might become a bit hard to read/follow. Foreach is probably more appropriate.

And here is the first working version of my code:

$xml2 = SimpleXMLElement($new_xml);
$current = 0;
$topics_list = array();
foreach($xml2->children() as $data) {
    $topics_list[$current]['chapter'] = (string) $data->chapter;
    $topics_list[$current]['title'] = (string) $data->title;
    $topics_list[$current]['content'] = (string) $data->content;
    $current++;
}

Thanks again to @Jack, @CoursesWeb and @fab for their investigation.

The problem is that you not get the name of the xml element.

To get the name of the xml element, apply elm->getName()

In your code should be:

if ($data->getName() === 'chapter')

For more details about traversing and getting xml elements with Simplexml, see this tutorial: http://coursesweb.net/php-mysql/php-simplexml

There are several mistakes.

1. return value of xpath()

$root = $xml2->xpath("//topic");

Here you assign $root to a list of all nodes retrieved by the XPath //topic. So, when you iterate over it with

foreach($root as $data)

$data refers to each of the <topic> elements, not the children of those.

2. comparison of SimpleXMLElements with strings

Let's assume, you loop over the right elements and $data refers to the <chapter> element: then the following expressions are true:

$data == 'Some value'
(string) $data === 'Some value'

But you cannot do a type safe comparison (===) between a SimpleXMLElement and a string, and the conversion to string does not result in the element name. What you want to do is:

if ($data->getName() === 'chapter')

3. how to get the text value

it should already be clear from the explanation above but you also will have to replace

$data->chapter

with

(string) $data