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Having trouble with siblings

by madbee (Acolyte)
on Jun 30, 2013 at 08:22 UTC ( #1041556=perlquestion: print w/replies, xml ) Need Help??
madbee has asked for the wisdom of the Perl Monks concerning the following question:

Hello! Still trying to parse the same XML as before - but now having trouble with siblings. I have 2 versions of the xml file. Need to come up with a generic script to extract the values in either cases. Pasting the XML first and then my attempt.

When I run my script, it doesnt return any siblings. just 1.

XML File: Version 1 <root> <part> <sect> <header> 1. Purpose and rationale <P>purpose 1</p> <p>Purpose 2</p> <p>purpose 3</p> <l> <li>purpose list 1</li> <li>list2</li> </l> </header> </sect> </part> </root>

Objective:In this scenario, I need to search for Purpose and rationale. If found, need to extract all siblings between <header> and </header>

The same section Purpose and rationale can exist in another xml but in different format. The challenge is to have 1 generic script to handle both scenarios.

XML Scenario 2:

<root> <part> <sect> <header> 1. Purpose and rationale <P>purpose 1</p> <p>Purpose 2</p> <p>purpose 3</p> <l> <li>purpose list 1</li> <li>list2</li> </l> <p>2. Some other heading</p> <p>content 1</p> <p>content 2</p> </header> </sect> </part> </root>

For scenario 2, I need to extract all the siblings under Purpose and rationale only until "Some other heading". This heading title can change. The only identifier is that the node begins with a number.

In this xml content from 2 headers is mixed up. so i only need to extract the content from the siblings of the "purpose and rationale" section

My attempted code is below:

my $dom = XML::LibXML->new->parse_file($file); my $study_str = 'Purpose and rationale|Study purpose|Study ration +ale' for my $search ('/root/part/sect/header') { my $nodeset = $dom->find($search); foreach my $node($nodeset -> get_nodelist) { $node -> string_value; if ($node =~ m/$study_str/i) { my $protocol = $node; print $protocol,"\n"; #go to the next sibling while ($node -> { Node }) { if ($node -> { Node } -> getNextSibling ) { $node -> { Node } = $node -> getNextSibling; return $node -> { Node }; } } } } }

This only returns the value within the header tags and none of the children. obviously,i'm doing something wrong.Hoping for some help here to extract the content I need.

Thanks again for your help and apologies if the question is not clear

Regards, Madbee

Replies are listed 'Best First'.
Re: Having trouble with siblings
by poj (Monsignor) on Jun 30, 2013 at 14:27 UTC

    This extracts all the childnodes into an array. I've printed them out with numbers and delimiter so you can see them individually. I suggest you loop through them extracting all or any that you want.

    #!perl use strict; use XML::LibXML; my $dom = XML::LibXML->load_xml( IO => *DATA ); my $study_str = 'Purpose and rationale|Study purpose|Study rationale'; for my $search ('//header') { my $nodeset = $dom->find($search); foreach my $node ($nodeset->get_nodelist){ if ($node =~ m/$study_str/i){ my @childnodes = $node->nonBlankChildNodes(); my $n=1; for (@childnodes){ print '#'.$n++.'# '.$_->toString."##\n\n"; } } } } __DATA__ <root> <part><sect> <header> 1. Purpose and rationale doc 1 <p>purpose 1</p> <p>Purpose 2</p> <p>purpose 3</p> <ul> <li>purpose list 1</li> <li>list2</li> </ul> <p>2. Some other heading</p> <p>content 1</p> <p>content 2</p> </header> </sect></part> </root>
Re: Having trouble with siblings
by Anonymous Monk on Jun 30, 2013 at 14:34 UTC

      Aha, the node test node() will select all types of nodes, even text() nodes

      • so find a <header> which contains 'rationale'
      • and select every child node of that header
      • and filter this nodeset for nodes which have following-sibling with tagname  <l> or which have tagname  <l>
      xmllint.exe --xpath " //header[ contains(.,'rationale') ]/node()[ fol +lowing-sibling::l or self::l] " fudge 1. Purpose and rationale <p>purpose 1</p> <p>Purpose 2</p> <p>purpose 3</p> <l> <li>purpose list 1</li> <li>list2</li> </l> 2. Purpose and rationale <p>2 purpose 1</p> <p>2 Purpose 2</p> <p>2 purpose 3</p> <l> <li>2 purpose list 1</li> <li>2 list2</li> </l>

      Naturally if there are more than one  <l> you can limit to first <l> with position()  xmllint.exe --xpath " //header[ contains(.,'rationale') ]/node()[ following-sibling::l[ position()=1 ] or self::l[ position()=1 ]  ]   " fudge

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