Re: While loop conditions in Perl

A more perlish way to do this, and the way that confines your variable to the scope of the loop, is like this:

while( my $nextline = <IN> ){
  chomp;
  last unless $nextline eq '';   # exits the loop unless empty line
  print "Nextline is empty\n";
}                                # now $nextline goes out of scope
[download]

UPDATE: Yes, as cheekuperl noticed, that should be chomp $nextline;

Aaron B.
Available for small or large Perl jobs; see my home node.

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Re^2: While loop conditions in Perl by cheekuperl (Monk) on Jul 18, 2012 at 22:09 UTC
I was wondering if chomp statement in your code should be like : `chmop $nextline; #chomp uses $_ by default` [download]	[reply] [d/l]
Re^3: While loop conditions in Perl by joemaniaci (Sexton) on Jul 18, 2012 at 22:20 UTC
Well I actually don't use chomp anymore, I can't really explain it but I have come across files that just didn't agree with chomp. So I use... `$string =~ s/^\s+//; $string =~ s/\s+$//;` [download] To remove any whitespace(including newlines) before the first character and after the last character on the line, as well as... `@fi = split(/\s+/, $nextline);` [download] ... to break apart the line by spaces. This whole issue I was having actually initiated with my while loop being constructed with... `while(@fi[0] eq'') { $nextline = readline<IN>; //remove whitespace //split the line, but I think I included my accidentally so that +I had my @fi = split..... }` [download] ...so that I also changed my scope inside the while loop accidentally by using... `my $nextline = ...` instead of... `$nextline = ...`	[reply] [d/l] [select]
Re^4: While loop conditions in Perl by cheekuperl (Monk) on Jul 19, 2012 at 06:00 UTC
Thats alright my friend. You could've said it all in one line :) I can't really explain it but I have come across files that just didn't agree with chomp Now this has made me curious! Could you please elaborate? (This might help me if I come across any such situation and I have no clues about what's going on)	[reply]
Re^5: While loop conditions in Perl by SuicideJunkie (Vicar) on Jul 19, 2012 at 14:41 UTC
Re^5: While loop conditions in Perl by joemaniaci (Sexton) on Jul 20, 2012 at 16:06 UTC
Re^6: While loop conditions in Perl by cheekuperl (Monk) on Aug 09, 2012 at 07:59 UTC
Re^4: While loop conditions in Perl by Anonymous Monk on Oct 18, 2013 at 21:31 UTC
I believe you have probably encountered line feeds followed by new lines ( \r\n ). In this case, just adjust the input record separator ( local $/ = "\r\n"; )	[reply]