#!/usr/bin/perl

use strict;
use warnings;
use Statistics::Descriptive::Weighted;

my @data = (1..2000000);
my $stat = Statistics::Descriptive::Full->new(); 
$stat->add_data(@data); 
print $stat->quantile(1), "\n";

##</code><code>##

#!/usr/local/bin/perl

use strict;
use warnings;

my @numbers = (1..2000000);
printf "Percentile %d%% at %f\n", $_, percentile($_,\@numbers)
for qw/25 75/;

sub percentile {
    my ($p,$aref) = @_;
    my $percentile = int($p * $#{$aref}/100);
    return (sort @$aref)[$percentile];
}