cutoff.pl

use strict;
use warnings;
use List::Util qw(sum);

my @data = ();
my @all = ();
my $keisu = 3;
my $cutoff = 0;
my $linenum = 0;

while(<>){
	$linenum++;
	next if $linenum == 1;
	chomp;

	my @line = split /\t/;

	if (/^\:/ || eof()){
		print $_ . "\n";

		@data = sort {$a <=> $b} @data;
		my $num = scalar @data;
		my @half = @data[0..int($num/2 -1)];
		my $half_num = scalar @half;

		$cutoff = sum(@half)/$half_num	* $keisu;
		
		my @up = grep {$_->[1] >= $cutoff} @all;	

		for (@up){
			print join " " , @$_;
			print "\n";
		}
		@data = ();
		@all = ();
	}

	else{
		push @all, \@line;
		if ($line[0] >=1200 && $line[0] <=1500){
			push @data, $line[1];
		}	
	}

}