Pull XML nodeValue into php Variable - php

Question

I am trying to assign the <all> / <avg> value in this XML code to a variable, so that I can use it for calculations. But when I do this, and try to print the value, I get a blank screen. Can someone please help?
<stats>
<type id="a">
<buy>
<volume>698299009</volume>
<avg>17.94</avg>
<max>18.45</max>
<min>1.00</min>
</buy>
<sell>
<volume>16375234</volume>
<avg>21.03</avg>
<max>24.99</max>
<min>20.78</min>
</sell>
<all>
<volume>714674243</volume>
<avg>18.01</avg>
<max>24.99</max>
<min>1.00</min>
</all>
</type>
</stats>
The php code I am using is as follows:
$xml = simplexml_load_file("values.xml");
$unit_value = $xml->xpath("/stats/type[#id='a']/buy/avg/")->nodeValue;
echo $unit_value;

Answer 1

Please refer documentation here, $xml->xpath should return you the array. The docs also shows an example of how to access text nodes. Below is an excerpt from the docs
<?php
$string = <<<XML
<a>
<b>
<c>text</c>
<c>stuff</c>
</b>
<d>
<c>code</c>
</d>
</a>
XML;
$xml = new SimpleXMLElement($string);
/* Search for <a><b><c> */
$result = $xml->xpath('/a/b/c');
while(list( , $node) = each($result)) {
echo '/a/b/c: ',$node,"\n";
}
/* Relative paths also work... */
$result = $xml->xpath('b/c');
while(list( , $node) = each($result)) {
echo 'b/c: ',$node,"\n";
}
?>
which produces output as
/a/b/c: text
/a/b/c: stuff
b/c: text
b/c: stuff
which is I suppose exactly what you need.

Answer 2

xpath returns an array of SimpleXMLElement objects .. so you can do this :
$unit_value = $xml->xpath("//stats//type[#id='a']//buy//avg");
echo (string)$unit_value[0]; // cast to string not required
Working example here
or if you are using PHP => 5.4 you can do this :
$unit_value = $xml->xpath("//stats//type[#id='a']//buy//avg")[0];
echo $unit_value;
Working example here