I think I get what you mean. A simple way of doing it would be to group them into two different arrays of arrays. Like so... 
#!/usr/bin/perl

use strict;
use warnings;

my (@cluster1, @cluster2);

open FILE, 'dataset.txt';

while (<FILE>){
  my @cols = split /\s+/;

  if ($cols[0] =~ m/\d/){
    if ($cols[2] < 200){ 
      push @cluster1, [@cols];
    }
    else {
      push @cluster2, [@cols];
    }
  }
}

# simple test to make sure it worked.

foreach my $row (@cluster1) {
  #print "$cluster1[$row]\n";
  print "@$row\n";
}

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In reply to Re: how to get clusters? by starX
in thread how to get clusters? by sirna

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