I believe that the recommended fastest way of doing this is
$cnt = $string =~ tr/a/a/;
Adding:
sub c_tr {
my ($c) = @_;
return $string =~ tr/$c/$c/;
}
to Edan's benchmarking example (Hi Ephraim), I get:
Rate c_regexp c_index c_tr
c_regexp 100849/s -- -69% -91%
c_index 326938/s 224% -- -70%
c_tr 1085603/s 976% 232% --
Yossi
----- Original Message ----
From: Yuval Kogman <[EMAIL PROTECTED]>
To: Perl in Israel <[email protected]>
Sent: Monday, September 3, 2007 2:42:55 PM
Subject: Re: [Israel.pm] count chars
You can use the goatse.cx operator:
my $matches =()= ( $string =~ /a/g );
This will evaluate the regex in list context and only then coerce it
to scalar context.
On Mon, Sep 03, 2007 at 13:38:05 +0300, Amir E. Aharoni wrote:
> What is the best way to count the number of times that a character
> appears in a string?
>
> Currently i do this:
>
> ----
> my $string = "abracadabra";
> my @matches = ($string =~ /a/g);
> print scalar @matches; # 5
> print "@matches"; # a a a a a
> ----
>
> Is there a way to do it without the intermediate array?
>
> This doesn't work:
>
> ----
> my $string = "abracadabra";
> print scalar ($string =~ /a/g); # prints 1!
> ----
>
> I can use this:
>
> ----
> my $matches = ($string =~ s/(a)/$1/g);
> ----
>
> It replaces the characters with itself and returns the number of
> substitutions, but it doesn't improve readability.
>
> Any other ideas?
>
> --
> Amir Elisha Aharoni
> words: http://aharoni.wordpress.com/
> music: http://www.myspace.com/tzabari/
> _______________________________________________
> Perl mailing list
> [email protected]
> http://perl.org.il/mailman/listinfo/perl
--
Yuval Kogman <[EMAIL PROTECTED]>
http://nothingmuch.woobling.org 0xEBD27418
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