Janek Schleicher wrote:
>
> John W. Krahn wrote at Tue, 20 Aug 2002 22:43:55 +0200:
> >
> > You can use \d instead of [0-9], \D instead of [^0-9] and \S instead of
> > [^\s].
> >
> > /^(\D+)(\d+ |)(\d+\/\S+)(.*)$/
> ^^^^^^^
>
> That's still an ugly and slow way to have an optional match
> better write it as
>
> m!^(\D+)(\d+ )?(\d+/\S+)(.*)$!
A quick test:
use Benchmark;
my $yes = 'x' x 100 . 333;
my $no = 'x' x 100 . 'www';
timethese( -15, { bar => sub { $yes =~ /^(\D+)(\d+|)/ and $no =~ /^(\D+)(\d+|)/ },
qm => sub { $yes =~ /^(\D+)(\d+)?/ and $no =~ /^(\D+)(\d+)?/ } } );
Gives the results:
Benchmark: running bar, qm, each for at least 15 CPU seconds...
bar: 15 wallclock secs (15.02 usr + 0.00 sys = 15.02 CPU) @ 23001.33/s
(n=345480)
qm: 15 wallclock secs (15.38 usr + 0.00 sys = 15.38 CPU) @ 21303.45/s
(n=327647)
So it isn't really slower. YMMV
John
--
use Perl;
program
fulfillment
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