Is what you had in mind something like this? 
use warnings;
use strict;

my $horiz_data = <<"HORIZ" ;
|||01/01/2007|01/02/2007|01/03/2007|06/29/2007|
|JOHN DOE|Event1|PARTY|CLASS|WORK|VACATION|
|JOHN D0E|Event2|CLASS|CLASS|WORK|PARTY|
|JANE DOE|Event1|PARTY|CLASS|WORK|VACATION|
|JANE DOE|Event2|CLASS|CLASS|WORK|PARTY|
HORIZ

my @horiz = split "\n", $horiz_data;

my @dates = split '\|', shift @horiz;
shift @dates;
shift @dates;
shift @dates;


for my $line (@horiz) {

   my @flds = split '\|', $line;
   shift @flds;
   my $name = shift @flds;
   my $event = shift @flds;

   my @dates_copy = @dates;
   for my $date (@dates_copy) {
      print "|$name|$date|$event|",shift(@flds),"|\n";
   }

} # for $line

[download]
which produces 
|JOHN DOE|01/01/2007|Event1|PARTY|
|JOHN DOE|01/02/2007|Event1|CLASS|
|JOHN DOE|01/03/2007|Event1|WORK|
|JOHN DOE|06/29/2007|Event1|VACATION|
|JOHN D0E|01/01/2007|Event2|CLASS|
|JOHN D0E|01/02/2007|Event2|CLASS|
|JOHN D0E|01/03/2007|Event2|WORK|
|JOHN D0E|06/29/2007|Event2|PARTY|
|JANE DOE|01/01/2007|Event1|PARTY|
|JANE DOE|01/02/2007|Event1|CLASS|
|JANE DOE|01/03/2007|Event1|WORK|
|JANE DOE|06/29/2007|Event1|VACATION|
|JANE DOE|01/01/2007|Event2|CLASS|
|JANE DOE|01/02/2007|Event2|CLASS|
|JANE DOE|01/03/2007|Event2|WORK|
|JANE DOE|06/29/2007|Event2|PARTY|

[download]

In reply to Re: How to Change Data Layout from Horizon to Vertical by rodion
in thread How to Change Data Layout from Horizon to Vertical by Anonymous Monk

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