Hello all, I just started learning Perl and I get stuck on a basic file processing :

Congratulations, you're not the first :) start with perlintro, print, split, Text File Parsing

Use Text::CSV or Text::xSV

Examples at

• join - join two files according to a common key
• part - split up files according to column value
• Merge two files with similar column entries
• Opening multiple files ( csvpaste.pl )
• Open multiple file handles?
• X, Y Table structure
• How to extract the particular residues from PDB files(text csv split hash bioperl)
• Select only desired features from a text (text csv split hash bioperl)
• Sort on Table headers (text csv split hash bioperl)
• I need help joining tab-delimited files/tables!
• split then join based on common value in field
• Smart way to read a file vertically?
• reformatting tab delimited file
• edit a CSV and "in-place" replacement
• Re: Reversing a mysql table, transpose-tsv -- invert a tab-delimited table

• Text::CSV

  examples/csv2xls	Script to onvert CSV files to M$Excel
  examples/csv-check	Script to check a CSV file/stream
  examples/csvdiff	Script to shoff diff between sorted CSV files
  examples/parser-xs.pl	Parse CSV stream, be forgiving on bad lines

 [CSV hash ] CSV hash

Best way to match a hash with large CSV file

perl hash to CSV using Text::CSV_XS

Issue parsing CSV into hashes?

Veriable Length Array/Hash derived from CSV to populate an XML

extracting data from CSV files and making hash of hashes

Re^2: build hash from csv file

Encoding a hash in perl before saving it as a CSV file

hash from CSV-like structure

Read the csv file to a hash....

Parsing CSV into a hash

build hash from csv file

Converting a CSV list to a list of hashrefs naming the fields

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

my %hash;
my @names;
while(<DATA>)
{
    my ($Groupname,@Data) = split(/\s+/,$_);

    foreach(@Data)
    {
       my ($name,$count) = split(/\|/,$_);
       unless ( grep( /^$name$/, @names ) ) {
       push(@names,$name);
     }
     $hash{$Groupname}->{$name}++;
    }
}
&Format(\%hash,\@names);
sub Format
{
        my ($hash_ref,$name_ref) = @_;

        my @Names = sort @$name_ref;
        my @Group_names = keys %{$hash_ref};

        my $filename = "test.txt"; #Give File Path
        open my $fh, '>>', $filename or die "Can't write to '$filename
+': $!\n";

        print $fh "\t@Names\n";
        foreach my $g_name (@Group_names)
        {
            print $fh "$g_name\t";
            foreach my $name(@Names)
            {
                unless (exists $hash_ref->{$g_name}->{$name})
                {
                    print $fh qq{0\t};
                }
                else
                {
                print $fh $hash_ref->{$g_name}->{$name}.qq{\t};
                }
            }
            print OUT qq{\n};
        }

}
__DATA__
Group1: somo|112345478 somo|734567233 homo|233689876
Group2: somo|904686712 somo|891145662 somo|106736432
Group3: aomo|397634567 aomo|123446789
Group4: aomo|905672345 aomo|120846789
[download]

Use open() function to open the input file and read each line using while loop, instead of using <DATA>

Updated the file open() safer method, as per Arunbear advise! Thanks Arunbear ++

op op op op open 3 arg style !