John Dennis wrote:
> On Tue, 2006-11-28 at 16:57 -0800, Yan Seiner wrote:
>
>>Fist off, I'm a total newbie when it comes to libxml. I've been able to
>>work my way through some examples, and produce working code, but I'm not
>>entirely happy with the result, and I would like some advice.
>>
>>I have an XML tree that looks like this:
>>
>><root>
>> <plc id="1">
>> <some stuff/>
>> </plc>
>> <plc id="2">
>> <some other stuff/>
>> </plc>
>></root>
>>
>>I have a relatively small number (< 50) of the plc nodes, but the whole
>>tree is pretty big.
>>
>>What is the best (or simplest way) to retrieve the information for plc 2?
>>
>>
>
>
> xpath is the simplest and most powerful
>
>>Should I pull all of the plc elements using xmlXPathEvalExpression, and
>>then iterate over them with xmlGetProp looking for an id attribute with
>>a value of "2"?
>>
>>
>
> no need to iterate, just create an xpath expression which specifies id=2
>
> off the top of my head the expression would be "/[EMAIL PROTECTED]"2"]"
>
> just google xpath syntax or xpath examples, you'll turn up a ton
OK, thanks a lot for the above!
I'm working with an embedded platform, so it took me a bit to get all of
the required libxml stuff together and rebuild PHP with libxml support....
Now I have xpath working with PHP. Yaay!
Ok, now for the PHP + xml question:
I am trying to get the base node of a schedule; I've attached a small
portion of my XML file below. What I would like to do is to get the
root of a schedule, and then iterate with foreach through all of the
children. This is the function I came up with and of course it doesn't
work. I don't understand how I am supposed to work with the object that
the xpath_eval[_expression] returns. I've also tried the child_nodes
method and that fails as well.
Hopefully there is a PHP expert on the list who can shed some light on this.
Thanks,
--Yan
function loadSchedule($pivotID, $schedName, $schedNum) {
$dom = domxml_open_file("/tmp/test.conf");
$xpath = xpath_new_context($dom);
// find base node for our schedule
$pat = '//root/[EMAIL PROTECTED]"' . $pivotID . '"]/'
. $schedName . '[EMAIL PROTECTED]"' . $schedNum . '"]';
print $pat;
$baseNode = xpath_eval($xpath,$pat);
var_dump($baseNode);
$lines = xpath_eval_expression($xpath,'/line',$baseNode);
var_dump($lines);
print "\nOK\n";
foreach($lines->nodeset as $line) {
var_dump($line);
}
}
<root>
<pivot id="1">
<water id="1">
<line id="1">
<bearingTo>120.0</bearingTo>
<WetDry>1</WetDry>
<FwdRev>0</FwdRev>
<event>0</event>
<speed>10</speed>
</line>
<line id="2">
<bearingTo>180.0</bearingTo>
<WetDry>1</WetDry>
<FwdRev>1</FwdRev>
<event>0</event>
<speed>45</speed>
</line>
</water>
<pivot>
</root>
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