Re: replace / with \ using regular expressions?

For replacing a single, known character, then regular expressions are the wrong tool. You need the tr/// operator as has already been pointed out.

The difference in performance is impressive:

$ cat bench
#!/usr/bin/perl

use strict;
use warnings;

use Benchmark 'cmpthese';

sub regex_subst {
  $_ = 'this/is/a/string';
  s|/|\\|g;
}

sub tr_subst {
  $_ = 'this/is/a/string';
  tr|/|\\|;
}

cmpthese(1_000_000, {
          s  => \&regex_subst,
          tr => \&tr_subst,
         });
$ ./bench
        Rate    s   tr
s   287356/s   -- -75%
tr 1162791/s 305%   --
$
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Comment on Re: replace / with \ using regular expressions? Download Code

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Re^2: replace / with \ using regular expressions? by Juerd (Abbot) on Jun 21, 2009 at 23:09 UTC
You need the tr/// operator No, you don't need it. TIMTOWTDI, and s///g is as understandable and easy to write just like tr///. The difference in performance is impressive But typically completely irrelevant for the performance of scripts/programs of any size. This optimization feels pretty immature. When will doing 287356 of these operations per second ever be anything other than fast enough?	[reply]
Re^2: replace / with \ using regular expressions? by Anonymous Monk on Jun 20, 2009 at 14:22 UTC
hi daveorg, Thanks for making this clear to me.	[reply]
Re^3: replace / with \ using regular expressions? by Marshall (Canon) on Jun 20, 2009 at 15:40 UTC
I would just point out that the Perl functions on Windows don't care about / vs \. If you calling a Perl function leave it in a/b/xyz format. Of course a command to the Windows shell is different.	[reply]