Re: [OT] Perl pattern matching

[Michael Naumann <mnaumann@giga-stream.de>]

On Friday 06 December 2002 16:53, Jörg Johannes wrote:
> Hi List
> 
> Sorry for coming in here with such a question, but this list ahs perl 
> gurus, and response is much faster than comp.lang.perl.misc (and I need 
> the answer fast...)
> 
> Here it comes:
> In "Programming Perl (german translation) there is an example for how to 
> skip lines that start with the hash sign:
> 
> LINE: while ($line = <INFILE>) {
>   next LINE if /^#/;       # Should skip lines that start with the hash 
> sign.
>   # what to do with non-comment-lines....
> }
> 

I think, the problem is, that you assign to $line but test to $_, which 
in fact is not set.
So either change your code to :
 LINE: while (<INFILE>) {
   next LINE if /^#/;       # Should skip lines that start with the hash sign.
   # what to do with non-comment-lines....
 }
or to
 LINE: while ($line = <INFILE>) {
   next LINE if $line =~ /^#/;       # Should skip lines that start with the hash sign.
   # what to do with non-comment-lines....
 }

> When I try to use it, I get an error message:
> Use of uninitialized value in pattern match (m//) at ./rhodanid.pl line 
> 138, <INFILE> line 1
> for all lines of the file coming in via <INFILE>
> 
> Any idea how to skip comment-lines?
> 
> thanks
> joerg
> 
> PS.: The book is written for Perl 5.006, I think, and I use 5.8 (from 
> sid). Did the pattern matching change?

Don't know and don't think so.

HTH, Michael