Re: Re: Expressing myself

.*? is at least better than .*, but I prefer to be a little more explicit and would use something like <([^>]+)> instead.

Something you also might want to watch out for is your use of $1 without verifying the match actually succeeded, leaving you with something you probably didn't expect.

--k.

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Re: Re: Re: Expressing myself by how do i know if the string is regular expression (Initiate) on May 12, 2001 at 22:12 UTC
Just out of curiosity, I benchmarked this. `#!/usr/bin/perl -w use Benchmark; $email = '<silvers@op.net>'; Benchmark::cmpthese(100000000, { '.' => sub { $email =~ m/.?\<(.?)\>/ }, '^>' => sub { $email =~ m/<([^>]+)>/ } } );` [download] Results: `Benchmark: timing 100000000 iterations of ., ^>... .: 1437 wallclock secs (1432.85 usr + 0.06 sys = 1432.91 CPU +) @ 69788.05/s (n=100000000) ^>: 645 wallclock secs (645.23 usr + 0.06 sys = 645.29 CPU) @ + 154969.08/s (n=100000000) Rate . ^> .* 69788/s -- -55% ^> 154969/s 122% --` [download] - FrankG	[reply] [d/l] [select]

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Re: Re: Re: Expressing myself
by how do i know if the string is regular expression (Initiate) on May 12, 2001 at 22:12 UTC

#!/usr/bin/perl -w
use Benchmark;

$email = '<silvers@op.net>';

Benchmark::cmpthese(100000000,
    {   
        '.*'    => sub { $email =~ m/.*?\<(.*?)\>/ },
        '^>'    => sub { $email =~ m/<([^>]+)>/    }
    }
);
[download]

Results:

Benchmark: timing 100000000 iterations of .*, ^>...
        .*: 1437 wallclock secs (1432.85 usr +  0.06 sys = 1432.91 CPU
+) @ 69788.05/s (n=100000000)
        ^>: 645 wallclock secs (645.23 usr +  0.06 sys = 645.29 CPU) @
+ 154969.08/s (n=100000000)
       Rate   .*   ^>
.*  69788/s   -- -55%
^> 154969/s 122%   --
[download]

- FrankG

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