Hi monks, I have another question that is probably super simple, but I keep hitting a wall. Let's say I have a list of paths that represent a tree, like so:

Valentine's Day
Valentine's Day|Cards
Valentine's Day|Flowers
Valentine's|Candy
Valentine's|Telegrams

[download]
It is assumed that the the order represents the tree's order. The problem is that the tree has some structure errors -- parents are missing in certain locations. I want to create something that would create the missing paths where necessary. For example: 

Valentine's Day
Valentine's Day|Cards
Valentine's Day|Flowers
Valentine's
Valentine's|Candy
Valentine's|Telegrams

[download]

I realize the above structure makes no sense, but I wanted to illustrate the problem with my current script. It won't notice 'Valentine's' as a path that needs to be created, because the term exists in the previous path. I think I need to tighten my regex, but I am not sure. Can someone help me out? Thanks!

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



while(<DATA>) {
    chomp;
    my $path = $_;
    my @paths = split /\|/, $path;
    my $parent = $paths[-2];
    my $child = $paths[-1];
    my $prev_path;


    if ($prev_path !~/^$parent$/) {
        my $message = 'created new path!';
        my @new_paths = @paths;
        my $discard = pop @new_paths;
        my $new_path = join '|', @new_paths;
        print $new_path . "\t" . $message . "\n";
    }


    print $path . "\n";


    $prev_path = $path;
}

__DATA__
Valentine's Day
Valentine's Day|Cards
Valentine's Day|Flowers
Valentine's|Candy
Valentine's|Telegrams

[download]

In reply to Tree path analyzer regex problem (maybe other issues)? by bryank

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