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 ?

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;
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abc xyz,10
xyz pqr,2
pqr stq,0.1
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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};
}
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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?

I have tried adding if conditions as shown in following code but it is not skipping to add comment line and empty line. Am I doing something wrong?

   while(my $colref = $csv->getline ($csv_fh))
   {
      if (scalar(@$colref) =~ /^#/) {
        last;
        }
      if (scalar(@$colref) =~ /^s+$/) {
        last;
        }
      
      $output_hash{shift @{$colref}} = $colref;
   }
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config file

#ksjlasjda

abc xyz,10
xyz pqr,2
pqr stq,0.1
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