in reply to Re^3: Can you write a faster code to perform this task?
in thread Can you write a faster code to perform this task?

Well TIMTOWTDI with two chained tr is not necessarily fast. :)

But who knows, try to benchmark... :)

Cheers Rolf

(addicted to the Perl Programming Language and ☆☆☆☆ :)

  • Comment on Re^4: Can you write a faster code to perform this task?

Replies are listed 'Best First'.
Re^5: Can you write a faster code to perform this task?
by Your Mother (Archbishop) on Sep 29, 2014 at 16:02 UTC

    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%     --

    [download]

    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).

[reply]
[d/l]
[select]
      > 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]

In Section Seekers of Perl Wisdom