Re: Re: Re: text extract

Now suppose i need to make a generic code that just searched for the keywords "publications" and "interests" within a given page, how do i reform the code.

That's no moon, that's a space station -- Obiwan Kenobi.

To do text extraction based on known pattern is easy if you know what the section start and finish look like in general. However you are looking for a generic algorithm on logical text extraction, you need to build a text-classification/pattern-recognition engine, and that's going to be very very difficult. Difficult, but not impossible. But that's way beyond me, besides I don't want to lose too many brain cells over this. ;-)

I will only cover the easy way, ie, (deterministic) text extraction based on a set of known patterns...

use strict;
use warnings;
use Data::Dumper;

# build a hash of known patterns for each known web site
my %patterns = (
    'www.foo.com' => {
        start  => "<h3><font[^>]*><b><!--KEY--></b>",
        finish => "(?<!</font>\n)<br>",
    },

    'www.bar.com' => {
        start  => "...",
        finish => "...",
    },
);

my $html = do { local $/; <DATA> };

print ExtractSection($html, 'www.foo.com', 'Section 2'), "\n\n";
print ExtractSection($html, 'www.foo.com', 'Section 1'), "\n\n";
print ExtractSection($html, 'www.foo.com', 'Section 3'), "\n\n";

# -----------------------------------------------------

sub ExtractSection
{
    my ($html, $site, $section) = @_;

    my $ps = $patterns{$site}->{start};
    my $pf = $patterns{$site}->{finish};

    $ps =~ s/<!--KEY-->/$section/;
    $pf =~ s/<!--KEY-->/$section/;

    my ($text) = $html =~ /($ps.*?$pf)/sm;
    return $text;
}

__DATA__
<HTML>
<h3><font size=+1><b>Section 1</b></font>
<br>
<li>Item 1
<li>Item 2
<li>Item 3
<br>
<h3><font size=+1><b>Section 2</b></font>
<br>
<li>Item 4
<li>Item 5
<li>Item 6
<br>
<h3><font size=+1><b>Section 3</b></font>
<br>
<li>Item 7
<li>Item 8
<li>Item 9
<br>
</HTML>
[download]

And the output -

<h3><font size=+1><b>Section 2</b></font>
<br>
<li>Item 4
<li>Item 5
<li>Item 6
<br>

<h3><font size=+1><b>Section 1</b></font>
<br>
<li>Item 1
<li>Item 2
<li>Item 3
<br>

<h3><font size=+1><b>Section 3</b></font>
<br>
<li>Item 7
<li>Item 8
<li>Item 9
<br>
[download]

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