Change ${data}{$name} to be a hash instead of an array.

#!/usr/bin/perl

use strict;
use warnings;

my %data;

while (<DATA>) {
  chomp;
  next unless /\S/;

  my ($name, $num) = /(.*)\s+(\d+)/;

  $data{$name}{$num} = 1;
}

foreach my $name (sort keys %data) {
  print "$name ";
  print join ',', sort { $a <=> $b } keys %{$data{$name}};
  print "\n\n";
}

__END__
Chee S. L. 8

Cheng T. H. 5

Cheng T. H. 2

Chetan M. 4

Cheng T. H. 2
[download]