Why aren't these values being added to my array as strings?

问题

Further to my question here, I'm actually wondering why I'm not getting strings added to my array with the following code.

I get some HTML from an external source with this:

$doc = new DOMDocument();
@$doc->loadHTML($html);
$xml = @simplexml_import_dom($doc); // just to make xpath more simple
$images = $xml->xpath('//img');
$sources = array();

Here is the images array:

Array
(
    [0] => SimpleXMLElement Object
        (
            [@attributes] => Array
                (
                    [alt] => techcrunch logo
                    [src] => http://s2.wp.com/wp-content/themes/vip/tctechcrunch/images/logos_small/techcrunch2.png?m=1265111136g
                )

        )
   ...
)

Then I added the sources to my array with:

foreach ($images as $i) {   
  array_push($sources, $i['src']);
}

But when I print the results:

 echo "<pre>";
 print_r($sources);
 die();

I get this:

Array
(
    [0] => SimpleXMLElement Object
        (
            [0] => http://www.domain.com/someimages.jpg
        )
    ...
)

Why isn't $i['src'] treated as a string? Isn't the original [src] element noted where I print $images a string inside there?

To put it another way $images[0] is a SimpleXMLElement, I understand that. But why is the 'src' attribute of THAT object not being but into $sources as a string when I reference it as $i['src']?

回答1:

Why isn't $i['src'] treated as a string?

Becaue it isn't one - it's a SimpleXMLElement object that gets cast to a string if used in a string context, but it still remains a SimpleXMLElement at heart.

To make it a real string, force cast it:

array_push($sources, (string) $i['src']);

回答2:

Because SimpleXMLElement::xpath() (quoting) :

Returns an array of SimpleXMLElement objects

and not an array of strings.

So, the items of your $images array are SimpleXMLElement objects, and not strings -- which is why you have to cast them to strings, if you want strings.

来源：https://stackoverflow.com/questions/5668561/why-arent-these-values-being-added-to-my-array-as-strings

标签

php

arrays

simplexml

domdocument