Re^2: Any help available for a newbie to XML::LibXML?

Hi again

I've written a bit more code to test it out and it is very slow doing the findnodes when I'm already at a position in the tree.

I've written this test script:

my $parser = XML::LibXML->new();
my $doc    = $parser->parse_file($filename);
my @devinfo = $doc->findnodes('//Device/Dev_Info');

foreach my $devinfo (@devinfo) {
    my($dev) = $devinfo->findnodes('./dev_name');
    print $dev->to_literal, "\n";
}
[download]

The first findnodes runs very quickly (< 1 sec) but the one in the loop is a lot slower. But I don't know why. Doesn't it just have to examine the nodes "under" the current devinfo tag?

Am I doing something wrong with the findnodes call here?

Thanks, ~ Michael

Comment on Re^2: Any help available for a newbie to XML::LibXML? Download Code

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Re^3: Any help available for a newbie to XML::LibXML? by Corion (Patriarch) on Mar 03, 2008 at 08:51 UTC
The only thing that I see from looking at your code that might be responsible would be that `my($dev) = $devinfo->findnodes('./dev_name');` [download] actually finds many nodes just to throw them all away except for the first. Maybe do it this way to check how many nodes you find: `my @found_devices = $devinfo->findnodes('./dev_name'); warn "Found " . scalar(@found_devices); my $dev = $found_devices[0];` [download] But that's just a shot in the dark. Actually looking at your XML, it shouldn't find more than one device.	[reply] [d/l] [select]
Re^4: Any help available for a newbie to XML::LibXML? by wardy3 (Scribe) on Mar 03, 2008 at 22:49 UTC
Thanks Corion - interesting thought. but unfortunately it's only finding 1 at a time. The speed is about 2 per second which is quite atrocious. And I agree, it should only find 1 too. I'm guessing there's a fixed overhead for findnodes which would make sense for what I'm seeing Anyway, I've got a few more replies to try out :-) and maybe it is time to re-visit my old friend XSLT Thanks again for the reply - I'll post back any more findings	[reply]