I have a feeling I may be about to learn something... ;-) 
use strict;
use warnings;


use Benchmark   qw( cmpthese );

my $results = cmpthese( -10, {
                              'r3' => sub {
                                  my $string = "  stuff  ";
                                  $string =~ s/^\s//g;
                                  $string =~ s/\s$//g;
                                  $string =~ s/\s+$//g;
                              },
                              'r1' => sub {
                                  my $string = "  stuff  ";
                                  $string =~ s/^\s|\s$|\s+$//g;
                              },
                             }
                      );

[download]
       Rate  r1  r3
r1 295926/s  -- -1%
r3 299980/s  1%  --

[download]
Updated: Now that I see GrandFather's detailed Benchmark below, I see that my error was to use a short string. When I change to 
my $string = (' ' x 1000) . 'x' . (' ' x 1000);

[download]
matching GrandFather's, I get the following: 
       Rate   r3   r1
r3  61890/s   -- -79%
r1 297607/s 381%   --

[download]
So Lies, damn lies, and benchmarks (with the wrong data), indeed.

In reply to Re^5: question about reg exp engine by broomduster
in thread question about reg exp engine by chuckd

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