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Re: optimizing /\s*,\s*/
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From:
H.Merijn Brand
Date:
September 8, 2003 11:03
Subject:
Re: optimizing /\s*,\s*/
Message ID:
20030908200211.AD7A.H.M.BRAND@hccnet.nl
On Mon 08 Sep 2003 19:36, "Jeff 'japhy' Pinyan" <japhy@perlmonk.org> wrote:
> A lot of times, when people want to split a string into comma-separated
> fields, they use something like
>
> @fields = split /\s*,\s*/, $string;
Yes, I do a lot of split m/\s*\|\s*/, $_, -1
What's naive? It's probably an 'Ahh, sure. Darn I forgot.' but enlighten me.
> Yes, naive, whatever, that's not the point. The point is that the regex
> engine matches \s*, and then looks for it to be followed by a comma.
> Could the engine be optimized to search FIRST for the NON-OPTIONAL comma,
> and then match all immediately preceding whitespace? That is, on a string
> like "abc def , ghi,...", the engine would first find the , and then
> subtract one from the beginning index of the match while the preceding
> character is whitespace?
>
> I'm not sure I know enough to implement this, but I'd think there'd be an
> improvement, especially in cases where the optional piece (\s*) is found
> frequently in the string.
--
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