XML::LibXML extracting datacolumn

deadpickle has asked for the wisdom of the Perl Monks concerning the following question:

I have an xml file with one of its child elements as:

<datacolumn name="Latitude" units="Degrees">
   <item value="40.9408"/>
   <item value="40.7698"/>
   <item value="40.5629"/>
   <item value="40.3019"/>
   <item value="39.9689"/>
   <item value="40.0589"/>
   <item value="39.9509"/>
   <item value="39.9149"/>
   <item value="39.4199"/>
   <item value="39.204"/>
   <item value="39.078"/>
   <item value="38.88"/>
   <item value="38.772"/>
   <item value="38.754"/>
   <item value="38.502"/>
   <item value="38.403"/>
   <item value="38.331"/>
   <item value="38.151"/>
   <item value="38.0251"/>
   <item value="37.9981"/>
   <item value="37.8901"/>
   <item value="37.8631"/>
   <item value="37.7461"/>
   <item value="37.4581"/>
   <item value="37.4491"/>
   <item value="37.2601"/>
   <item value="37.2691"/>
   <item value="37.1791"/>
   <item value="37.1971"/>
   <item value="37.0261"/>
   <item value="36.9541"/>
   <item value="36.9271"/>
   <item value="36.5042"/>
   <item value="36.5132"/>
  </datacolumn>
[download]

I want to extract this data using XML::LibXML but am not sure how. So far I have:

 #!/usr/bin/perl -w

use strict;
use XML::LibXML;

my $parser = XML::LibXML->new;
my $xmlfile = "20060402-201025.xml";
my $doc = $parser->parse_file($xmlfile);
my $element = $doc->getDocumentElement;

my @nodes = $element->getElementsByTagName('data');

foreach my $kid1(@nodes) {
    my $elname2 = $kid1 -> getName();
    print $elname2,"\n";
    my $lon = $kid1->getAttribute('Longitude');
    print $lon,"\n";
}
[download]

This doesnt work since the datacolumn is not an attribute. I'm not sure what it is. Any ideas?

Comment on XML::LibXML extracting datacolumn Select or Download Code

Replies are listed 'Best First'.
Re: XML::LibXML extracting datacolumn by ikegami (Patriarch) on Nov 04, 2009 at 00:00 UTC
Single column from the root: `my @lats = map $_->getValue(), $root->findnodes('//datacolumn[@name="Latitude"]/item/@value');` [download] All columns: `my %table; #for my $col_node ( $root->findnodes('//datacolumn') ) { for my $col_node ( $table_node->findnodes('datacolumn') ) { my $col_name = $col_node->getAttribute('name'); $table{$col_name} = [ map $_->getValue(), $col_node->findnodes('item/@value') ]; }` [download] I assumed the elements are in the null namespace. Update: Added second snippet. Update: s/name=/\@name=/	[reply] [d/l] [select]
Re^2: XML::LibXML extracting datacolumn by deadpickle (Pilgrim) on Nov 04, 2009 at 00:45 UTC
not getting anything with this code: `#!/usr/bin/perl -w use strict; use XML::LibXML; my $parser = XML::LibXML->new; my $xmlfile = "20060402-201025.xml"; my $doc = $parser->parse_file($xmlfile); my $element = $doc->getDocumentElement; my @nodes = $element->getElementsByTagName('data'); foreach my $kid1(@nodes) { my $elname2 = $kid1 -> getName(); print $elname2,"\n"; my @lats = map $_->getValue(),$kid1->findnodes('//datacolumn[name= +"Latitude"]/item/@value'); print @lats,"\n"; }` [download] The full xml is as follows: <?xml version="1.0"?> <!DOCTYPE datatable> <datatable> <datatype name="ClusterTable"> <stref> <location> <lat> <angle units="Degrees" value="41.003815"/> </lat> <lon> <angle units="Degrees" value="-93.634293"/> </lon> <ht> <length units="Meters" value="1000.000000"/> </ht> </location> <time units="secondsSinceEpoch" value="1144008625"/> </stref> <attr name="SubType"> <datacolumn name="SubType" units="dimensionless"> <item value="scale_0"/> </datacolumn> </attr> <attr name="scale"> <datacolumn name="scale" units="dimensionless"> <item value="0"/> </datacolumn> </attr> </datatype> <data> <datacolumn name="Latitude" units="Degrees"> <item value="40.9408"/> <item value="40.7698"/> <item value="40.5629"/> <item value="40.3019"/> <item value="39.9689"/> <item value="40.0589"/> <item value="39.9509"/> <item value="39.9149"/> <item value="39.4199"/> <item value="39.204"/> <item value="39.078"/> <item value="38.88"/> <item value="38.772"/> <item value="38.754"/> <item value="38.502"/> <item value="38.403"/> <item value="38.331"/> <item value="38.151"/> <item value="38.0251"/> <item value="37.9981"/> <item value="37.8901"/> <item value="37.8631"/> <item value="37.7461"/> <item value="37.4581"/> <item value="37.4491"/> <item value="37.2601"/> <item value="37.2691"/> <item value="37.1791"/> <item value="37.1971"/> <item value="37.0261"/> <item value="36.9541"/> <item value="36.9271"/> <item value="36.5042"/> <item value="36.5132"/> </datacolumn> <datacolumn name="Longitude" units="Degrees"> <item value="-93.5421"/> <item value="-92.9772"/> <item value="-92.8504"/> <item value="-92.7582"/> <item value="-92.6775"/> <item value="-92.2971"/> <item value="-91.3865"/> <item value="-90.9369"/> <item value="-92.6314"/> <item value="-92.009"/> <item value="-92.7698"/> <item value="-92.032"/> <item value="-92.8966"/> <item value="-92.251"/> <item value="-92.885"/> <item value="-91.9629"/> <item value="-92.2395"/> <item value="-92.1012"/> <item value="-88.3318"/> <item value="-92.3663"/> <item value="-88.0667"/> <item value="-88.228"/> <item value="-92.4931"/> <item value="-92.6775"/> <item value="-92.2395"/> <item value="-92.7698"/> <item value="-92.4585"/> <item value="-92.885"/> <item value="-91.8361"/> <item value="-92.9081"/> <item value="-88.8159"/> <item value="-93.104"/> <item value="-93.3346"/> <item value="-92.8274"/> </datacolumn> [download]	[reply] [d/l] [select]
Re^3: XML::LibXML extracting datacolumn by ikegami (Patriarch) on Nov 04, 2009 at 02:29 UTC
First of all, you change $root to $kid1. But I also missed a "@". `#!/usr/bin/perl -w use strict; use XML::LibXML; my $xmlfile = "20060402-201025.xml"; my $parser = XML::LibXML->new; my $doc = $parser->parse_file($xmlfile); my $root = $doc->getDocumentElement; my @lats = map $_->getValue(), $root->findnodes( '/datatable/data/datacolumn[@name="Latitude"]/item/@value' ); print "$_\n" for @lats;` [download]	[reply] [d/l]


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