Re^5: Can you write a faster code to perform this task?

tr is MUCH faster than s though. I tried to work this out but didn’t hit on trizen’s cleverness. So…

# (v5.18.2) built for darwin-2level
    'tr' => sub {
        $str =~ tr/M/~/sr=~tr/~//;
    },
-- 
count      3
regex      3
regex2     3
split      3
tr         3

            Rate regex2  split  regex  count     tr
regex2  169354/s     --   -62%   -65%   -75%   -94%
split   446500/s   164%     --    -7%   -34%   -85%
regex   481882/s   185%     8%     --   -29%   -84%
count   674634/s   298%    51%    40%     --   -78%
tr     3044813/s  1698%   582%   532%   351%     --
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Update: as trizen noted in his code, the /r flag to tr came in at 5.14. It won’t work on older Perls (update: <- stupid apostrophe begone).

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Re^6: Can you write a faster code to perform this task? by LanX (Saint) on Sep 29, 2014 at 17:56 UTC
> I tried to work this out but didn’t hit on trizen’s cleverness. me too / neither =) (tried /s but the returned count wasn't for groups) > the /r flag to tr came in at 5.14. It won’t work on older Perls If it's that fast using $str twice shouldn't be a big problem. Should be mentioned that `tr` is destructive, i.e. a safety copy of the string may be needed too. Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :)}	[reply]

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Re^6: Can you write a faster code to perform this task?
by LanX (Saint) on Sep 29, 2014 at 17:56 UTC

> I tried to work this out but didn’t hit on trizen’s cleverness.

me too / neither =)

(tried /s but the returned count wasn't for groups)

> the /r flag to tr came in at 5.14. It won’t work on older Perls

If it's that fast using $str twice shouldn't be a big problem.

Should be mentioned that tr is destructive, i.e. a safety copy of the string may be needed too.

Cheers Rolf

_{(addicted to the Perl Programming Language and ☆☆☆☆ :)}

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