-- Randal L. Schwartz, Perl hacker

Are you sure it's faster?

I have benchmarked this before. It is faster. With short matches, regexes are often faster. /^#/ is faster than substr($_, 0, 1) eq '#'. (all assuming you'll have more non-matches than matches, which is true when checking when checking for . and ..)

- Yes, I reinvent wheels.
- Spam: Visit eurotraQ.

I'd be interested in seeing your results. I did some some benchmarking too, and found that the regex is slower.

Here's the program (using my soon to be released 'Benchmark::Sized' module) and the results.

#!/usr/bin/perl
 
use strict;
use warnings qw 'all';

use Benchmark::Sized;

use vars qw /@array/;

my $stats = sized_timethese
    run_for    =>    2, 
    steps      =>    8, 
    start_size =>    1, 
    end_size   => 1000,
    seed       => sub {
        @main::array = map {join "" => map {chr rand 128} 1 .. $_ [0]}
+ 1 .. 20
    },
    code       => {
        regex  => 'my @foo = grep {! /^\.\.?\Z/} @main::array',
        ne     => 'my @foo = grep {$_ ne "." and $_ ne ".."} @main::ar
+ray',
    }
;

print "Runs/second for regex vs ne:\n";
print_timed $stats, type => 'sized';

__END__
Runs/second for regex vs ne:
Size         ne    regex
   1:  20744.28 12809.79   
   3:  22549.51 13048.06
   7:  23110.45 12337.91
  19:  21600.00 12560.28
  52:  21005.50 12276.56
 139:  19269.95 11891.63
 373:  18345.79 11220.29
1000:  14422.54  9634.74
[download]

Abigail