My data is like below 

Username | Roles | Type |date |SR NO|Remarks|
abc|admin |added | 01072015
abc|developer |deleted |01072015
abc|deploy |added |01072015
xyz |admin |deleted |01072015
xyz| deploy|deleted|01072015
cdf|deploy|added|01072015

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and i need to do the following a) i need to group based on the user, roles and concatenate the roles filed with the delimiter "," b) I need to create the output as below. 

Username |roles added |roles deleted |date
username |roles_added |roles deleted |date
abc |admin,deploy |developer |01072015 
xyz ||admin,deploy |01072015
cdf |deploy||01072015

[download]

In order to achieve this,am using the code below 

 use strict;
use warnings;
use diagnostics;
use Data::Dumper;

open(FIL,"report.txt") or die("$!");

my %k=();

while (my $line=<FIL>) {
      next if $. < 2;
        my ($user,$roles,$type,$dt,$empty1,$empty2)=split(/\|/,$line);

        push @{$k{$user}{$type}}, $roles;

}

my @names=(sort keys(%k));



foreach ( @names) {
   if ( @{$k{$_}{Added}} ne ''){
   print "${k{user}}\n";
   print   join ',', @{$k{$_}{Added}};
   print "\n";
   }
   if ( @{$k{$_}{Deleted}} ne '') {

   print join ',', @{$k{$_}{Deleted}};
   print "\n";
        }
}

[download]

The script fails with below error Can't use an undefined value as an ARRAY reference at report3.pl line 34, <FIL> line 23. at report3.pl line 34 Please help me how i can generate the output as expected. Many thanks

In reply to Aggregating the column based on the common column values by kanskr

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