Looping through SimpleXMLElement to access attributes - php

Question

I am trying process data retrieved with SimpleXML and am having great difficulty. I have read numerous threads here about this subject, they all LOOK like what I am doing, but mine are not working. Here's what I've got:
<ROOT>
<ROWS COMP_ID="165462">
<ROWS COMP_ID="165463">
</ROOT>
My code:
$xml = simplexml_load_file('10.xml');
foreach( $xml->ROWS as $comp_row ) {
$id = $comp_row->COMP_ID;
}
As I step through this in my debugger, I can see that $id is not set to the string value of COMP_ID, but becomes a SimpleXMLElement itself containing the CLASSNAME object. I've tried many variations of addressing this attribute but none work, including $comp_row->attributes()->COMP_ID and others.
What am I missing?

Answer 1

SimpleXML is an array-like object. Cheat sheet:
Unprefixed child elements as numeric-index or traversable
Does not include prefixed elements (NOTE, I really mean prefixed, not null-namespace! SimpleXMLElement handling of namespaces is a strange and arguably broken.)
first child: $sxe[0]
new SimpleXMLElement with a subset of matching elements: $sxe->ROWS, $sxe->{'ROWS'}
iterate children: foreach ($sxe as $e), $sxe->children()
Text content: (string) $sxe. SimpleXMLElement always returns another SimpleXMLElement, so if you need a string cast it explicitly!
Prefixed child elements:
$sxe->children('http://example.org') returns a new SimpleXMLElement with elements
in the matching namespace, with namespace stripped so you can use it like the previous section.
Attributes in null namespace as key-index:
specific attribute: `$sxe['attribute-name']
all attributes: $sxe->attributes()
$sxe->attributes() returns a special SimpleXMLElement that shows attributes as both child elements and attributes, so both the following work:
$sxe->attributes()->COMP_ID
$a = $sxe->attributes(); $a['COMP_ID'];
Value of an attribute: coerce to string (string) $sxe['attr-name']
Attributes in other namespaces:
all attributes: $sxe->attributes('http://example.org')
specific attribute: $sxe_attrs = $sxe->attributes('http://example.org'); $sxe_attrs['attr-name-without-prefix']
What you want is:
$xml = '<ROOT><ROWS COMP_ID="165462"/><ROWS COMP_ID="165463"/></ROOT>';
$sxe = simplexml_load_string($xml);
foreach($sxe->ROWS as $row) {
$id = (string) $row['COMP_ID'];
}

Answer 2

You're missing...
foreach( $xml->ROWS as $comp_row ) {
foreach ($comp_row->attributes() as $attKey => $attValue) {
// i.e., on first iteration: $attKey = 'COMP_ID', $attValue = '165462'
}
}
PHP Manual: SimpleXMLElement::attributes