Jay Savage wrote:
>
> I've actually found it depends partly on architecture, too; the regex
> engine seems better optimized on some platforms than others. I was
> quite surprised once when benchmarking a script on a fairly modern OS
> X/PPC machine (750MHz CRT iMac) and an ancient Linux box (166MHz PII
> Dell Dimension XPS PII running SuSE 9.1)--with both machines running
> 5.8.6--that the regex solution to the problem I was working on ran
> faster on the the Dell, but the index version ran faster on the Mac.
>
> The issue seemed to be the number of function calls. index beat the
> pants off m// on both machines for finding literals, of course, but
> once I had to perform two indexes, combining them both into a single
> regex ran faster on one machine and was only about 1% slower on the
> other.
>
> The relevance here is that once your looking for several things, I'd
> at least want to bechmark the regex, especially since we're firing up
> the regex engine for the first match anyway.
>
> My advice to the OP would be to benchmark all three of the following
> and see which comes out on top for him:
>
> grep /_${feed_date}_.*?\.wav\z/o, @dir_files;
> grep ((index($_, $feed_date) != -1) && (index($_, ".wav") != -1)),
> @dir_files;
> grep /\.wav\z/ && (index($_, $feed_date) != -1), @source_list;
> grep { /_${feed_date}_/ && /\.wav$/ } @dir_files;
Be careful with those matches to ensure you are matching the same things. For
example, the OP said he had file names something like:
ABCD_9Mar_somethingelse.wav
ABCD_19Mar_somethingelse.wav
If $feed_date is '9Mar' then your second and third examples will match both
file names and your second example will also match the file name:
ABCD_9Mar_some.wavthingelse.pdf
John
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