use warnings;
use strict;

use Benchmark;

open my $fh, '<', 'in.txt' or die $!;

timethese(1000000, {
            regex => '_regex',
            split => '_split',
        });

sub _regex {
    seek $fh, 0, 0;
    while (<$fh>){
        if (/^\d+\.\s+(?:N\/A\s+|\d+\s+){2}(\w+)/){
            #print "$1\n";
        }
    }
}
sub _split {
    seek $fh, 0, 0;
    LINE: while (<$fh>){
        my ($x, $one, $two, $test_name, @remaining) = split;
        for ($one, $two){
            next LINE unless $_ eq 'N/A' or $_ =~ /^\d+$/;
            #print "$test_name\n";
        }
    }
}

__END__
Benchmark: timing 1000000 iterations of regex, split...
     regex: 20 wallclock secs (17.97 usr +  3.04 sys = 21.01 CPU) @ 47596.38/s (n=1000000)
     split: 39 wallclock secs (35.57 usr +  3.35 sys = 38.92 CPU) @ 25693.73/s (n=1000000)