use Benchmark qw(timethese);
use strict;
use warnings;

my @array = (1 .. 100000);
timethese(100, {granfather => \&grandfather, usual => \&usual});

sub grandfather {
	return 1 if grep {$_ == 100000} @array;
}

sub usual {
	for my $a (@array) {
		return 1 if ($a == 100000);
	}
	return 0;
}

##</code><code>##

Benchmark: timing 100 iterations of granfather, usual...
granfather:  4 wallclock secs ( 3.58 usr +  0.00 sys =  3.58 CPU) @ 27.95/s (n=1
00)
     usual:  4 wallclock secs ( 4.13 usr +  0.00 sys =  4.13 CPU) @ 24.24/s (n=1
00)

##</code><code>##

Benchmark: timing 100 iterations of granfather, usual...
granfather:  3 wallclock secs ( 3.58 usr +  0.00 sys =  3.58 CPU) @ 27.95/s (n=1
00)
     usual:  0 wallclock secs ( 0.00 usr +  0.00 sys =  0.00 CPU)
            (warning: too few iterations for a reliable count)

##</code><code>##

Benchmark: timing 100 iterations of granfather, usual...
granfather:  4 wallclock secs ( 3.69 usr +  0.03 sys =  3.72 CPU) @ 26.89/s (n=1
00)
     usual:  2 wallclock secs ( 2.08 usr +  0.00 sys =  2.08 CPU) @ 48.12/s (n=1
00)