I have two arrays roles added and roles deleted, want to merge them and write in this order in perl - text-processing

Question

I have another scenario.
My file has the following fields:
Username | Roles | Type |date |
abc|admin |added | 01072015
abc|developer |deleted |01072015
abc|deploy |added |01072015
xyz |admin |deleted |01072015
xyz| deploy|deleted|01072015
cdf|deploy|added|01072015
Note here, the date is going to be the same day, so no change
now, I want this to be printed as
username |roles_added |roles deleted |date
abc |admin,deploy |developer |01072015
xyz ||admin,deploy |01072015
cdf |deploy||01072015
I tried the below approach given, but didn't work out for me. Please guide me.
#!/usr/bin/perl
open(FIL,"report.txt") or die("$!");
my %k=();
while (my $line=<FIL>) {
my ($user,$roles,$type,$dt)=split(/\|/,$line);
$k{$user}{$roles}=1;
$k{$user}{$type}=1;
}
my #names=(sort keys(%k));
foreach my $name (#names) {
foreach my $value ( (keys(%{$k{$name}})) ){
print "$value ";
}
print "$name\n";
}
print " i am here \n";
while( my ($k, $v) = each %$k ) {
print "key: $k, value: $v.\n";
}

Answer 1

When dealing with complex data structures, Data::Dumper is your friend. Try adding use Data::Dumper to your code and then print Dumper \%k just after you've finished building your %k hash. You'll see something like this:
$VAR1 = {
'xyz' => {
' deploy' => 1,
'deleted' => 1
},
'Username ' => {
' Type ' => 1,
' Roles ' => 1
},
'xyz ' => {
'deleted ' => 1,
'admin ' => 1
},
'cdf' => {
'deploy' => 1,
'added' => 1
},
'abc' => {
'deleted ' => 1,
'deploy ' => 1,
'developer ' => 1,
'added ' => 1,
'admin ' => 1
}
};
See how the keys in the sub-hashes are names after two types of things. Half of them are the role names and half of them are "added" or "deleted". It's going to be really hard to get anything useful out of that data structure, so let's try something different.
Where you had:
$k{$user}{$roles}=1;
$k{$user}{$type}=1;
Try this instead:
push #{$k{$user}{type}}, $role;
Now our data structure looks like this:
$VAR1 = {
'xyz' => {
'deleted' => [
' deploy'
]
},
'xyz ' => {
'deleted ' => [
'admin '
]
},
'cdf' => {
'added' => [
'deploy'
]
},
'abc' => {
'deleted ' => [
'developer '
],
'added ' => [
'admin ',
'deploy '
]
}
};
I think you can see that it's far easier to get the information you want out of this data structure. It's basically:
foreach (#names) {
print join ',', #{$k{$_}{added}};
print join ',', #{$k{$_}{deleted}};
}
You'll need to change the code a little to get exactly what you want.
Oh, and please get into the habit of adding use strict and use warnings to all of your code. They would have shown you why the debugging output at the end of your original code wasn't working.
Update: I threw together a complete solution.
#!/usr/bin/perl
use strict;
use warnings;
use 5.010;
my %k;
<>; # Skip header
while (<>) {
chomp;
my ($user, $roles, $type, $dt) = split(/\s*\|\s*/);
push #{$k{$user}{$type}}, $roles;
$k{$user}{date} = $dt;
}
say 'username |roles_added |roles deleted |date';
foreach my $name (sort keys %k) {
say "$name |",
join(',',#{$k{$name}{added} || []}), ' |',
join(',',#{$k{$name}{deleted} || []}), ' |',
$k{$name}{date};
}
You need to pass it the name of the input file as a command line argument.