Re^2: How to find content between KEYWORD and BLANKLINE then print it

I'll ++ your post as soon as I get votes. It still contains a mistake though. Since =~ is of higher precedence than .., your code is actually parsed as ($line =~ /X/i) .. /^\s*$/ which means the second regex will be applied on $_. Adding parentheses like this: $str =~ (/A/../B/) won't work either because this will apply the regular expressions first, on $_ (and this also happens to be the range operator, not flip flop).

Here, using the default variable $_ is the best option for readability:

while (<DATA>)
{
  if (/A/../B/)
  {
     print;
  }
}
__DATA__
1
2
A
3
4
B
5
6
[download]

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Re^3: How to find content between KEYWORD and BLANKLINE then print it by johngg (Canon) on Jan 06, 2016 at 23:51 UTC
The wording of the OP seems to imply that the blank line that ends the range should not actually be printed, as 1nickt attempts. Adding another `&&` condition after the flip-flop achieves that. `$ perl -Mstrict -Mwarnings -E ' open my $inFH, q{<}, \ <<EOD or die $!; Seb Xavier Peter Roland Jim Xerox Paddle Yoyo EOD while ( <$inFH> ) { print if ( m{X} .. m{^\s$} ) && ! m{^\s$}; }' Xavier Peter Xerox Paddle $` [download] I hope this is of interest. Cheers, JohnGG	[reply] [d/l] [select]
Re^4: How to find content between KEYWORD and BLANKLINE then print it by choroba (Cardinal) on Jan 07, 2016 at 13:39 UTC
As documented in perlop, the flip-flop operator appends `E0` to its return value for the last line, so you can exclude it directly by inspecting the value: `while (<>) { my $m = /X/ .. /^\s$/; print if $m && $m !~ /E0$/; }` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7*2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re^3: How to find content between KEYWORD and BLANKLINE then print it by ChrisCK (Initiate) on Jan 06, 2016 at 23:44 UTC
Thank you both very much! This is what ended up working perfectly- `use strict; use warnings; my $file = $ARGV[0]; open( my $fh, '<', $file ) or die "Can't open $file: $!"; while ( <$fh> ) { if ( /Error:/i .. /^\s*$/ ) { print; } } close $fh;` [download] Error: was my keyword and I wanted all of the error message below it until a blank line was found. Thanks again!	[reply] [d/l]
Re^3: How to find content between KEYWORD and BLANKLINE then print it by 1nickt (Canon) on Jan 07, 2016 at 01:48 UTC
Thanks for the correction. I was hewing as closely as possible to the OP's code and didn't test before posting; I guess I've always used it with `$_`. Updated and noted in my reply. The way forward always starts with a minimal test.	[reply] [d/l]
Re^4: How to find content between KEYWORD and BLANKLINE then print it by johngg (Canon) on Jan 07, 2016 at 11:22 UTC
You can still use a lexical but you have to be explicit about what is being matched, also taking care with the difference in precedence of `and` and `&&`. With lower precedence `and`:- `$ perl -Mstrict -Mwarnings -E ' open my $inFH, q{<}, \ <<EOD or die $!; Seb Xavier Peter Roland Jim Xerox Paddle Yoyo EOD while ( my $line = <$inFH> ) { print $line if $line =~ m{X} .. $line =~ m{^\s$} and $line !~ m{^\s$}; }' Xavier Peter Xerox Paddle $` [download] Higher precedence `&&` requires parentheses:- `$ perl -Mstrict -Mwarnings -E ' open my $inFH, q{<}, \ <<EOD or die $!; Seb Xavier Peter Roland Jim Xerox Paddle Yoyo EOD while ( my $line = <$inFH> ) { print $line if ( $line =~ m{X} .. $line =~ m{^\s$} ) && $line !~ m{^\s$}; }' Xavier Peter Xerox Paddle $` [download] Cheers, JohnGG	[reply] [d/l] [select]