如何使用PHP在XML文档树中选择节点的第N个子节点？

Question

Consider the following example:

<query xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" yahoo:count="3" yahoo:created="2014-03-28T13:30:16Z" yahoo:lang="en-US">
<results>
<strong class="js-mini-profile-stat" title="8">8</strong>
<strong class="js-mini-profile-stat" title="0">0</strong>
<strong class="js-mini-profile-stat" title="1,643">1,643</strong>
</results>
</query>

I want to get that "strong" node with value of 1,643

I'm doing it like this:

$tw=$_GET["tw"];

function twitter($tw) {
$furl = file_get_contents("http://query.yahooapis.com/v1/public/yql?q=SELECT%20*%20from%20html%20where%20url=%22https://twitter.com/".$tw."%22%20AND%20xpath=%22//a[@class=%27js-nav%27]/strong%22&format=xml");

$api = simplexml_load_file($furl);
$followers = $api->results->strong[3];
return $followers;
}

But obviously, it returns error. There are 3 strong nodes, how do I select the third one? Help!

Answer 1

To get the 3rd <strong> node, do:

$followers = $api->results->strong[2];

because indices start at 0 .

If you want to select the element by its title instead of its position, use xpath :

$followers = $api->xpath("//strong[@title = '1,643']")[0]; // with PHP >= 5.4

or with PHP < 5.4:

$followers = $api->xpath("//strong[@title = '1,643']");
$followers = $followers[0];

see it working: https://eval.in/128263