danny0085 has asked for the wisdom of the Perl Monks concerning the following question:

I need to extract links from a html file (not all). Here are the xpaths 

/html/body/p/a
/html/body/p[2]/a 
/html/body/p[3]/a
....
/html/body/p[66]/a

[download]

how can extract the links with TreeBuilder?

here is what I have I do not know how to use the findvalues function 

 
$mech->get($url);
$content = $mech->response()->decoded_content(); 
my $tree = HTML::TreeBuilder::XPath->new;
$tree->parse($content);
$tree->eof;
@res = $tree->findvalues(???);#

[download]

Replies are listed 'Best First'.
Re: Help with xpath and TreeBuilder
by Gangabass (Vicar) on Jun 29, 2012 at 11:04 UTC

    It's really easy:

    #!/usr/bin/perl

use Modern::Perl;
use HTML::TreeBuilder::XPath;
use Data::Dumper;

local $/;
my $html = <DATA>;
my $tree = HTML::TreeBuilder::XPath->new_from_content($html);

my @values = $tree->findvalues('/html/body/p/a');

say Dumper(@values);

__DATA__
<html>
<body>
<p><a href="1.html">Link Text 1</a></p>
<p><a href="2.html">Link Text 2</a></p>
<p><a href="3.html">Link Text 3</a></p>
<p><a href="4.html">Link Text 4</a></p>
</body>
</html>

    [download]
[reply]
[d/l]

      Its even easier :) 

      my @xpaths = qw{
/html/body/p/a
/html/body/p[2]/a 
/html/body/p[3]/a
....
/html/body/p[66]/a
};
my $allXpaths = join ' | ', @xpaths;
my @values = $tree->findvalues;

      [download]

      I don't know about other xpath interpreters, but treebuilder::xpath (and xsh ) allows this

      This query is probably faster 

      /html/body/p[
position()=1
or  position()=2
or  position()=3
or  position()=66
]/a

      [download]

      Or this one 

      /html/body/p[
(
  (
    position() > 0
    and position() < 4
  )
  or
  (
    position()=66
  )
)
]/a

      [download]

      Though this one won't work with your html  //a[ position()=4] because each //a is at  //a[ position() = 1] because each //a is the only (first) child of its parent ( p ) --- I guess now I know how position() works

[reply]
[d/l]
[select]
Re: Help with xpath and TreeBuilder
by Anonymous Monk on Jun 29, 2012 at 06:19 UTC

    here is what I have I do not know how to use the findvalues function

    Really? findnodes takes xpaths, so just give it some xpaths

[reply]
      Give 64 xpaths is not a good solution I need a reg expression or something similar
[reply]

        What makes 64 XPath expressions not a good solution? Maybe you want a loop?

[reply]

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