Unable to replace targeted newlines in a string

benchrifa has asked for the wisdom of the Perl Monks concerning the following question:

Hello everybody,

This is my code:

 
#!/usr/bin/perl

my $string = "P5§2\nAAA\nBBB\nCCC\nP6§21\n";                    

            
$string =~ s/^(P\d+[^\n]*?\n)
            (([^\n]+)
            (\n))+
            (?:P\d+[^\n]*?)$ 
            /$1$2/xsmig;#
            
print "\$string  is \n$string \n";
[download]

I got this output:

P5º2
CCC
[download]

And I would like to get this one:

P5º2
AAABBBCCC
[download]

Thank you for your help

Benchrifa

Comment on Unable to replace targeted newlines in a string Select or Download Code

Replies are listed 'Best First'.
Re: Unable to replace targeted newlines in a string by moritz (Cardinal) on Oct 30, 2009 at 11:20 UTC
A quantified capturing group `(...)+` only stores the last match in the dollar-number variable it is associated with. So I recommend capturing all the AAA to CCC lines in a single capture, and remove the newlines from that in a separate step. Or even simple, split on `/^(?=P\d)/m` and then remove newlines from the chunks. Perl 6 - links to (nearly) everything that is Perl 6.	[reply] [d/l] [select]
Re^2: Unable to replace targeted newlines in a string by benchrifa (Novice) on Oct 30, 2009 at 13:32 UTC
Thank you for your explanation: crystal clear. Benchrifa	[reply]
Re: Unable to replace targeted newlines in a string by Marshall (Canon) on Oct 31, 2009 at 11:47 UTC
You have a string with a regular pattern of \n between the tokens. You want the first \n separated token and then the next 3 \n separated tokens. Maybe I have misunderstood the problem, but I would use split and slice for this job. `#!/usr/bin/perl -w use strict; my $string = "P5§2\nAAA\nBBB\nCCC\nP6§21\blah\nmore\n"; my ($first,@tokens) = (split(/\n/,$string))[0..3]; print "$first\n"; print @tokens,"\n"; __END__ Prints: P5§2 AAABBBCCC #Update: if you want the tokens in one $var, say $stuff, then #my $stuff = join("",@tokens); #print "$stuff\n"; # also prints: AAABBBCCC` [download]	[reply] [d/l]