This document discusses using Perl for natural language processing. It introduces NLP and its subfields. Perl is presented as a practical language for NLP with powerful regex capabilities. Perl linguistics modules are described that implement NLP algorithms for tasks like word counting, pattern matching, and named entity recognition. Examples are provided using modules like Lingua::EN::Sentence and Lingua::EN::NamedEntity. The talk concludes by mentioning potential for developing linguistics modules for Indian languages.

1. Natural Language Processing with Perl
G Jaganadh
C-DAC Thiruvananthapuram
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2. Talk Overview
Introduction
Natural Language Processing
Perl
Perl Lingua Modules
Some examples
Towards future
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3. Introduction
•Objectives of the talk
Introducing NLP techniques for Language Researchers
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4. Natural Language
Processing
Introduction to NLP
Sub fields in NLP
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5. Perl
•Practical Extraction and Report Language
Free and Open Source
Easy to Learn
Powerful regular Expressions for text searching
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6. Perl Lingua Modules
Perl Modules for Linguistic Processing
All most all modules are for English Dutch and other
European Languages
Powerful implementation of different NLP algorithms
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7. Some Examples
Counting words in a text
Pattern Matching
Use of Lingua::EN::Sentence
Use of Lingua::EN::NamedEntity
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8. Counting words
$text = <>;
while ($line = <>) {
$text .= $line;
}
#$text =~ tr/a-z��������A-Z���������n/cs;
@words = split(/n/, $text);
for ($i = 0; $i <= $#words; $i++) {
if (!exists($frequency{$words[$i]})) {
$frequency{$words[$i]} = 1;
} else {
$frequency{$words[$i]}++;
}
}
foreach $word (sort keys %frequency){
print "$frequency{$word} $wordn";
}
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9. Lingua::EN::Sentence
#!/usr/local/bin/perl -w
use Lingua::EN::Sentence qw( get_sentences add_acronyms );
## adding support for abbreviations
add_acronyms('lt','gen');
$/ = "nn";
while(<>) {
$sentences=get_sentences($_);
foreach $s (@$sentences) {
print "<s> $s </s>n";
}
}
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10. Lingua::EN::NamedEntity
#!/usr/bin/perl
use strict;
use Lingua::EN::NamedEntity;
while (<>) {
my $str = join 'n',<>;
#my $str = join 'n',<INP>;
my @entities = extract_entities($str);
foreach my $entity (@entities) {
print $entity->{entity},"n";
}
}
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11. Pattern Matching
while ($line = <>) {
if ($line =~ m/_____/ ) {
print $line ;
}
}
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12. Toward future
Lingua Modules for Indian Languages
Useful Stuff
•http://search.cpan.org/search?query=Lingua&mode=all
http://wiki.christophchamp.com/index.php/Perl/Modules/Lingu
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13. Question ?
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14. Thanks
jaganadhg@gmail.com
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