You should consider using s/\D+//g, as that's often a lot faster than s/\D//g. Here's a benchmark:

#!/usr/bin/perl

use strict;
use warnings;

use Benchmark;

my @sizes = (10, 25, 50, 100, 250, 500, 1000);
my @chars = ('A' .. 'Z', 'a' .. 'z', 0 .. 9);

our @d = map {join "" => map {$chars [rand @chars]} 1 .. $_} @sizes;

map {
    Benchmark::cmpthese timethese (-2 => {
        "simple_$sizes[$_]"   => '$_ = $::d[' . $_ . ']; s/\D//g;',
        "multiple_$sizes[$_]" => '$_ = $::d[' . $_ . ']; s/\D+//g;'
    }, 'none');
} 0 .. $#sizes
__END__
                Rate   simple_10 multiple_10
simple_10   196495/s          --        -15%
multiple_10 231225/s         18%          --
                Rate   simple_25 multiple_25
simple_25    89788/s          --        -50%
multiple_25 180650/s        101%          --
                Rate   simple_50 multiple_50
simple_50    47507/s          --        -64%
multiple_50 130727/s        175%          --
                 Rate   simple_100 multiple_100
simple_100    23206/s           --         -77%
multiple_100 103096/s         344%           --
                Rate   simple_250 multiple_250
simple_250   10488/s           --         -71%
multiple_250 36407/s         247%           --
                Rate   simple_500 multiple_500
simple_500    5046/s           --         -75%
multiple_500 20382/s         304%           --
                 Rate   simple_1000 multiple_1000
simple_1000    2528/s            --          -76%
multiple_1000 10549/s          317%            --
[download]

Abigail

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.