Have you looked at Text::CSV_XS? It can read CSV files and convert them to hashrefs respecting the headers.

Maybe when you have written the code, you can post the relevant parts here if you still need help.

Thanks. Following I am providing ReadCSV.pm, parameters.csv and getvalue.pl. It is working fine but I want to avoid any comments (starts with #) in parameters.csv and also any blank lines. How can I do that in ReadCSV.pm ?

ReadCSV.pm

package ReadCSV;
use strict;
use warnings;
use Data::Dumper;
use Text::CSV_XS;
use IO::File;

# Implementation:
sub csv_file_hashref {
   my ($filename) = @_;

   my $csv_fh = IO::File->new($filename, 'r');
   my $csv = Text::CSV_XS->new ();

   my %output_hash;

   while(my $colref = $csv->getline ($csv_fh))
   {
      $output_hash{shift @{$colref}} = $colref;
   }

   return \%output_hash;
}
1;
[download]

parameters.conf

abc xyz,10
xyz pqr,2
pqr stq,0.1
[download]

getvalue.pl

use strict;
use warnings;
use Data::Dumper;
use ReadCSV;

my $hash_ref = ReadCSV::csv_file_hashref('parameters.conf');
foreach my $key (sort keys %{$hash_ref}){
   print qq{$key:};
   print join q{,}, @{$hash_ref->{$key}};
   print qq{\n};
}
[download]

In the loop where you read the CSV, only store the row if it is not a comment?

Do the same for the blank lines?

Probably not the best example for learning, but this script does exactly what you want and a lot more: