> From: "Ph. Marek" <[EMAIL PROTECTED]>
> Date: Wed, 12 Feb 2003 08:42:57 +0100
>
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> Hello everybody,
>
> I've sometimes the task to analyse a string
> starting from a given position, where this position
> changes after each iteration. (like index() does)
>
>
> As this is perl there are MTOWTDIIP but I'd like
> to know the fastest.
>
> So I used Benchmark.pm to find that out. (script attached)
>
>
> Excerpt from script:
> "from_start" => sub { m/\S*\s+(\S+)/; },
> "re_dyn" => sub { m/^[\x00-\xff]{$pos}\S*\s+(\S+)/; },
> "re_once" => sub { m/^[\x00-\xff]{$pos}\S*\s+(\S+)/o; },
> "substr" => sub { substr($_,$pos) =~ m/\S*\s+(\S+)/; },
> "substr_set" => sub { $tmp=substr($_,$pos); $tmp =~ m/\S*\s+(\S+)/; },
>
> from_start is for comparision only as it should be.
> re_once is for comparision too as the index can't be adjusted.
> (and dynamically recompiling via eval() for changing indexes can't
> be fast enough)
Phil, please see the perlfunc entry for "pos" and the perlre section
on \G. This is what you need.
Luke
