Re: New regex trick...

So, to simply remove '.z' you go in all the trouble of doing the '.*' (glob all) match etc etc. Whereas a shorter version must be faster:

$str =~ s/\..$//;
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Unless I'm missing some other deeply nested point {griN}

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Re: Re: New regex trick... by japhy (Canon) on Jul 22, 2002 at 19:33 UTC
Yours is a very special case, because we know there's only one character after the last ".". Here is a benchmark I ran with my new patch: `use Benchmark 'cmpthese'; my $str = join '.', 'a' .. 'z'; cmpthese(-5, { old => sub { (my $x = $str) =~ s/(.)\../$1/ }, new => sub { (my $x = $str) =~ s/.\K\..// }, }); __END__ new: 109650.19/s (n=578953) old: 45258.35/s (n=241227)` [download] ... which is an incredible speed increase! _____________________________________________________ Jeff`[japhy]`Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area) `s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;`	[reply] [d/l]

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Re: Re: New regex trick...
by japhy (Canon) on Jul 22, 2002 at 19:33 UTC

use Benchmark 'cmpthese';
my $str = join '.', 'a' .. 'z';
cmpthese(-5, {
  old => sub { (my $x = $str) =~ s/(.*)\..*/$1/ },
  new => sub { (my $x = $str) =~ s/.*\K\..*// },
});
__END__
new: 109650.19/s (n=578953)
old:  45258.35/s (n=241227)
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_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area)
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

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