split: 17 wallclock secs (16.69 usr +  0.02 sys = 16.71 CPU) @ 59844.40/s (n=1000000)
    substr:  0 wallclock secs ( 0.74 usr +  0.00 sys =  0.74 CPU) @ 1351351.35/s (n=1000000)
    unpack:  1 wallclock secs ( 1.02 usr +  0.00 sys =  1.02 CPU) @ 980392.16/s (n=1000000)

##</code><code>##

     split:  2 wallclock secs ( 1.16 usr +  0.00 sys =  1.16 CPU) @ 862068.97/s (n=1000000)
    substr:  1 wallclock secs ( 0.70 usr +  0.00 sys =  0.70 CPU) @ 1428571.43/s (n=1000000)
    unpack:  0 wallclock secs ( 0.96 usr +  0.00 sys =  0.96 CPU) @ 1041666.67/s (n=1000000)

##</code><code>##

#!/usr/bin/perl -w
use strict;

use Benchmark;

use vars qw/$str/;

$str = "123456789asgdjlaskjglkajblnlbnlaqjteoijqotijwojgl;akjglkj";

timethese(shift || 1000000, {
    'unpack' => sub { my $char = getn_unpack($str, 1) },
    'substr' => sub { my $char = getn_substr($str, 1) },
    'split'  => sub { my $char = getn_split($str, 1) }
});

sub getn_unpack {
    return unpack "x" . ($_[1]-1) . "a", $_[0];
}

sub getn_substr {
    return substr $_[0], $_[1]-1, 1;
}

sub getn_split {
    return +(split //, $_[0],2)[$_[1]-1];
}