Re: Finding all substrings

Um, cool! But it leaks memory at an insane rate on 5.6.1.

Jeff Pinyan explained this one to me. The code in the regex captures the first instance of @ss, and keeps appending to it, 1023 new elements every time through the loop. You can fix the problem by using a static variable:

{ my @ss;
  sub substrings {
    @ss = ();
    $_[0] =~ /.*?(.+?)(?{push @ss, $1})(?!)/;
    @ss;
  }
}
[download]

--
Mark Dominus
Perl Paraphernalia

Comment on Re: Finding all substrings Download Code

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Re: Re: Finding all substrings by samtregar (Abbot) on Apr 24, 2002 at 21:28 UTC
Ah, much better. Now I can test it! Here are the results from my benchmark against /usr/dict/words, 100,000 iterations (my final code above is "new" and your code is "mjd"): `Benchmark: timing 100000 iterations of mjd, new, original... mjd: 17 wallclock secs (16.86 usr + 0.00 sys = 16.86 CPU) @ 59 +31.20/s (n=100000) new: 3 wallclock secs ( 2.70 usr + 0.01 sys = 2.71 CPU) @ 36 +900.37/s (n=100000) original: 17 wallclock secs (12.87 usr + 0.01 sys = 12.88 CPU) @ 77 +63.98/s (n=100000) Rate mjd original new mjd 5931/s -- -24% -84% original 7764/s 31% -- -79% new 36900/s 522% 375% --` [download] It looks like this solution is actually slower than the original... -sam	[reply] [d/l]

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Re: Re: Finding all substrings
by samtregar (Abbot) on Apr 24, 2002 at 21:28 UTC

Benchmark: timing 100000 iterations of mjd, new, original...
       mjd: 17 wallclock secs (16.86 usr +  0.00 sys = 16.86 CPU) @ 59
+31.20/s (n=100000)
       new:  3 wallclock secs ( 2.70 usr +  0.01 sys =  2.71 CPU) @ 36
+900.37/s (n=100000)
  original: 17 wallclock secs (12.87 usr +  0.01 sys = 12.88 CPU) @ 77
+63.98/s (n=100000)
            Rate      mjd original      new
mjd       5931/s       --     -24%     -84%
original  7764/s      31%       --     -79%
new      36900/s     522%     375%       --
[download]

-sam

[reply]
[d/l]