Another take. This will discard the first word or fragment, unless the first word is a match.
#!/usr/bin/perl
use strict;
use warnings;
die "No search terms supplied!" unless @ARGV;
my @words = @ARGV;
my $text;
{
local $/ = undef;
$text = <DATA>;
}
my $regex = join ( "|", @words ); # Words to highlight
my $expr = qr /(?i)($regex)/; # Compile regex
my $glen = 20; # Characters before and after the en
+d of match to grab.
{
no warnings 'uninitialized';
my ( $ls, $le, @results ); # $ls=prev span start, $le=prev span end
+, @results, results destination
# Markup any matches or exit block.
last unless $text =~ s/\b($expr)\b/[$1]/gi;
while ( $text =~ m/\b($expr)\b/sg or $le <= length ($text) ) {
my ($ipos,$spos,$epos); # char span positions
if ($ipos = pos($text)) { # If the last match succeded
$spos = $ipos - $glen > 0 ? $ipos - $glen : 0; # Range
+check
$epos = $ipos + $glen < length($text) ? $ipos + $glen : length
+($text);
# Assign to ($ls,$le) if this is our first time through and ne
+xt.
( $ls, $le ) = ( $spos, $epos ) and next unless $le;
}
if ( $spos and $spos < $le ) { # If we have a match and it inte
+rsects the last match
$le = $epos; # merge overlapping char spans
}
else {
# Lose the first word(possible fragment) unless the match is t
+he first word.
$ls = index($text," ", $ls) + 1 unless ($ls == 0);
push @results,substr( $text, $ls, $le - $ls ) ;
( $ls, $le ) = ( $spos, $epos ); # Set "las
+t position" to current.
}
last unless defined $spos; # End unle
+ss we have one more match
}
print '"',$_,'..."', "\n" foreach @results;
}
__DATA__
Regular expressions have always been a weak spot for me, and I've got
+a
question that's got me stumped. Here's the problem I'm trying to solv
+e.
I have somewhat large articles of text (returned from a search), what
+ I'd
like to do is capture the word and X number of words before and after
+ it
while tagging the matching word in the captured text. My inital thoug
+ht
was to try something like this. The problem I have is that if there i
+s
more than one term and they overlap, the nth term will not be annotat
+ed.
So my next thought is lookahead/lookbehind, but they don't capture.
Is there a way to do this with a single regex? Is a regex even the be
+st
way to do this? Thanks, -Lee
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.