in reply to Re: Re: Re: Simple Text Indexing
in thread Simple Text Indexing

I have implemented your function and added a few things from the code above including Cody Pendent's /\s+/ suggestion. I should have thought of these myself since I have done similar stuff in the past.

The resulting Storable file is only a few thousand K more than my original text index file. Now all I need to do is implement a searcher. I may re-write this into an object structure for ease of maintence at some point but I like the way things are headed. I still need to add the stop list in a hash but I have some obligations I need to take care of today. I have appended the code with my changes below.

I still have one more question however. Why do I need so many chdir functions? It seems unable to deal with "\..\index" or any of that sort of stuff. Thanks again!

use strict; use warnings; use utf8; use Storable; chdir "texts"; my @files = glob "*.txt"; my %file_idx = map {; $_ => index_file( $_, 5 ) } @files; chdir "\.."; chdir "index"; store \%file_idx, "text.idx"; =pod { 'foobar.txt' => { word => [ 1, 3, 5, 6 ], another => [ 5, 7, 2, ] }, 'barfoo.txt' => { ....... } =cut sub index_file { my $filename = shift; my $lines_of_context = $_[0] > 0 ? shift() : 1; open my $fh, "<", $filename or die "Couldn't open $filename: $!"; my @offsets; my %index; while ( my $line = <$fh> ) { push @offsets, tell $fh; my $offset = scalar( @offsets ) < $lines_of_context ? $offsets[0] : shift @offsets; for my $word ( split /\s+/, $line ) { $word = lc $word; $word =~ s/,$|\.$|\[|\]|\(|\)|;|:|!//g; if(&inStopList($word)) { next; }elsif($word =~ /p\.(\d)+/) { next; }elsif($word =~ /\-{5,}?/) { next; } push @{ $index{$word} }, $offset; } } close $fh or warn "Couldn't close $filename: $!"; return \ %index; } sub inStopList { my $word = shift; my @stopList = ("the", "a", "an", "of", "and", "on", "in", "by", " +with", "at", "he", "after", "into", "their", "is", "that", "they", "f +or", "to", "it", "them", "which"); foreach my $stopWord (@stopList) { if($word eq $stopWord) { return $word; } else { next; } } }

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Re: Re: Re: Re: Re: Simple Text Indexing
by ysth (Canon) on Nov 30, 2003 at 12:10 UTC
    Why do I need so many chdir functions? It seems unable to deal with "\..\index" or any of that sort of stuff.
    $x = "\..\index"; actually sets $x to "..index" (with a warning about the "\i" on some perl versions).

    Two things to fix: first, try using forward slash or doubling your backslash; second, '\..' is not meaningful, since the root directory should have no parent.

      Ah yes of course! It has been so long since I programmed that I had forgotten these things. Thanks!

Re: Re: Re: Re: Re: Simple Text Indexing
by diotalevi (Canon) on Dec 08, 2003 at 21:05 UTC

    Comments are inline.

    use strict; use warnings; use Storable; use vars qw($CONTEXT_LINES $TEXTS %STOPWORDS $INDEX); $CONTEXT_LINES = 3; @STOPWORDS{ # Prefer reading these from a file. qw( the a an of and on in by with at he after into their is that they for to it them which) } = (); # prefer texts/*.txt over "chdir 'text'; glob '*.txt'" my @files = glob "texts/*.txt"; my %file_idx = map {; $_ => index_file( $_, $CONTEXT_LINES ) } @files; store \%file_idx, "../index/text.idx"; =pod { 'text.idx' => { word => [ 1, 3, 5, 6 ], another => [ 5, 7, 2, ] }, 'barfoo.txt' => { ....... } =cut sub index_file { my $filename = shift; my $lines_of_context = $_[0] > 0 ? shift() : 1; open my $fh, "<", $filename or die "Couldn't open $filename: $!"; my @offsets; my %index; while ( my $line = <$fh> ) { push @offsets, tell $fh; my $offset = scalar( @offsets ) < $lines_of_context ? $offsets[0] : shift @offsets; # Prefer ' ' over /\s+/ here. See perlfunc about this. for my $word ( split ' ', $line ) { $word = lc $word; # Prefer character classes to alternation when possible $word =~ s/[,.]$|[\][();:!]//g; next if exists $STOPWORDS{$word} # Prefer (\d+) to (\d)+ (unless that is *really* what + you mean) or $word =~ /p\.(\d+)/ # Remove the '?' as that makes the operation always s +ucceed. or $word =~ /-{5,}/; push @{ $index{$word} }, $offset; } } close $fh or warn "Couldn't close $filename: $!"; return \ %index; }