http://www.perlmonks.org?node_id=988496


in reply to Finding duplicate text in a paragraph

Something like this? 

use strict;
use warnings;
my $text = 'The cat jumped over the dog. Smart cat! He jumped over the
+ dog. The cat jumped over the dog. Smart cat!';
my %seen;
my $longest = '';

while ($text =~ /\s*(.+?[!?.])/g) {
   $longest = $1  if $seen{$1}++ && length $1 > length $longest;
}
print $longest,$/;

[download]

Prints: 

The cat jumped over the dog.

[download]

But it's a whole other challenge if you mean "phrase" and not (terminated) sentence.

Replies are listed 'Best First'.
Re^2: Finding duplicate text in a paragraph
by Jester (Novice) on Aug 20, 2012 at 20:40 UTC
    Ah, I am kind of embarrassed not to have thought of this. I was so focused on look ahead, for some reason, but yeah, this works. The thing is, I need to match more than one sentence, potentially whole sections of texts can be duplicated and I need to find them. I will try your solution see how it goes. Thanks!
[reply]
Re^2: Finding duplicate text in a paragraph
by Jester (Novice) on Aug 20, 2012 at 20:45 UTC
    Oh, in fact this does not quite work. In that case, I would need it to print "The cat jumped over the dog." and "Smart cat!" as strings that are repeated.
[reply]

In Section Seekers of Perl Wisdom