Re: Trouble with m///g

[Dave Gray]

> TIMTOWTDI:
> 
>   @list = grep length==4, /\d+/g

Shouldn't that be:

 @list = grep length==4, $foo =~ /\d+/g;

Cool solution, I wouldn't have thought to do it that way. I'm getting
varying Benchmarking results, though. I think it might have something
to do with grep speedups from 5.6.1 to 5.8.0... can anyone confirm
this?

On a box with 4 Xeon 2gigs with 5.6.1 and Benchmark v1:
          Rate   grep wregex  regex
grep   55586/s     --   -13%   -23%
wregex 64061/s    15%     --   -12%
regex  72569/s    31%    13%     --

But, on another box with 1 AMD 1gig with 5.8.0 and Benchmark v1.0501:
          Rate wregex  regex   grep
wregex 31437/s     --   -14%   -18%
regex  36470/s    16%     --    -5%
grep   38212/s    22%     5%     --


Confusing!

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

my ($aa);
$aa = "1111 2222aa3333 444 55555555 6666 7777-8888";

sub regex { my @aa = $aa =~ /(?<!\d)\d{4}(?!\d)/g }

# Wiggins ;-)
sub wregex { my @aa = $aa =~ /(?<!\d{4})\d{4}(?!\d{4})/g }

sub grep { my @aa = grep length==4, $aa =~ /\d+/g }

cmpthese(100000, {
  regex => \&regex,
  wregex => \&wregex,
  grep  => \&grep,
});

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