I didn't like that article a bit. If you want to improve the performance of your Perl program Perl Monks is a much better resource. If I recall correct there has been nodes about this before. (Update: or see When Perl is not quite fast enough as Corion pointed out.)

By the way, in this example, an even quicker way of producing a string that repeats the alphabet 999,999 times would be to use: 
$concat = 999999 x 'abcdefghijklmnopqrstuvwxyz';

[download]

It must be rather embarrassing to make this obvious mistake that no one that writes an article about Perl should make.

A bit further down the article I read "Better still, in a simple calculation like this one or for any straightforward loop work, use map:", and then the author uses map BLOCK in void context instead of a for loop. Overlooking style issues it's still not a very good advice to me: 

use Benchmark 'cmpthese';
use strict;
use warnings;

my @stuff = 1 .. 20000;

cmpthese(-3, {
    'for EXPR' => sub {
        my $a = 0;
        ++$a for @stuff;
    },
    'for BLOCK' => sub {
        my $a = 0;
        for (@stuff) { ++$a }
    },
    'map BLOCK' => sub {
        my $a = 0;
        map { ++$a  } @stuff;
    },
    'map EXPR' => sub {
        my $a = 0;
        map ++$a, @stuff;
    },
});
__END__
            Rate map BLOCK  map EXPR for BLOCK  for EXPR
map BLOCK 50.4/s        --       -4%      -44%      -49%
map EXPR  52.3/s        4%        --      -42%      -47%
for BLOCK 89.9/s       78%       72%        --       -9%
for EXPR  98.6/s       96%       89%       10%        --

This is perl, v5.8.0 built for MSWin32-x86-multi-thread

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From there on, I didn't give the article much credibility nor read it too closely. I did notice some either ignorant or poorly expressed statements, but I won't even bother elaborating. Update: Although it raised some valid points it didn't elaborate when necessary -- I find it far too "simple".

ihb

See perltoc if you don't know which perldoc to read!
Read argumentation in its context!

In reply to Re: Optimize Perl by ihb
in thread Optimize Perl by Anonymous Monk

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