#!/usr/bin/perl -w
use strict;
use Benchmark 'cmpthese';

my $string = "this is a string" x 300;

cmpthese(10000000, {
	'index' => sub {
		my $res;

		$res = index($string, "this", 0);
		$res = index($string, "string");
		$res = rindex($string, "string");
	},
	regex   => sub {
		my $res;

		$res = $string =~ /^this/;
		$res = $string =~ /string/;
		$res = $string =~ /string$/;
	}
});
...