Hi Thomas,
a few comments on your code.
On Monday 10 May 2010 13:45:53 Thomas Bätzler wrote:
> Finalfire <blog.h...@gmail.com> asked:
> > Hello guys! I'm skilling regex using Perl and i've some trouble about
> > a simple try:
> > i've a string like:
> >
> > $string = "HELLOOOOAAABBCCCC";
> >
> > and i want to manipulate in that way: HELL4O3ABB4C;You can simply
> > notice that when i have 3 or more occurrences of a character, i want
> > to substitute all the occurrences and write "nC" where n is how times
> > the character C is found on a string.
> >
> > So, in regex (i think there are so many way to do it but i wish to do
> > with regex, just skilling...) i write:
> >
> > $string =~ s/(.)\1\1+/$1/;
> >
> > but how can i get the number of the occurrences in the string of that
> > pattern?
>
> #!/usr/bin/perl -w
>
use warnings is preferable to the -w flag.
> use strict;
>
> my $string = "HELLOOOOAAABBCCCC";
>
> print "$string\n";
>
> $string =~ s/(.)\1{2,}/length($&).$1/eg;
Please don't use $& as it slows down all subsequent regular expression matches
considerably. See the warning about it on perldoc perlvar. Instead wrap up the
entire match in an extra parentheses, like Shawn and I demonstrated.
In any case, you get bonus points for writing a working program.
Regards,
Shlomi Fish
>
> print "$string\n";
>
> __END__
>
> HTH,
> Thomas
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