my @fds;
for (1..200){
  open my $fds[$_], '<', "datafile$_" or die $!;
}

for my $ln (1..948){
  print "$ln has ";
  for my $fdn (1..200){
    my $line = <$fds[$fdn]>;
    my $field3 = get_third_field_using_whatever_csv_method($line);
    print $field3;
    print ' ' unless $fdn == 200;
  }
  print "\n";
}