my $string='aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
my @chars=split //,$string;

timethese(50000,{
	'Substr'=>sub{
		my $string='aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
		for (my $i=0;$i<length $string; $i++) {
			my $char=substr $string,$i,1;
		}
	},
	'pre_splitted'=>sub{
		foreach my $char (@chars) {
		
		}
	},
	'Split'=>sub{
		my @string=split //,'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
		foreach my $char (@string) {
			
		}
	}
});