Print line from file only once even if occurrence of pattern is more than once in the line

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

Replies are listed 'Best First'.
Re: Print line from file only once even if occurrence of pattern is more than once in the line by LanX (Saint) on Mar 29, 2015 at 17:48 UTC
You most likely have a loop over lines doing different checks. Use `next` after the first successful match to parse the next line. Otherwise you should show us some code of what you tried, such that we understand were your problem is. See also How do I post a question effectively? Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :)} PS: Je suis Charlie!	[reply]
Re^2: Print line from file only once even if occurrence of pattern is more than once in the line by jayu_rao (Sexton) on Mar 29, 2015 at 17:59 UTC
Thanks Rolf. You are right. The code snippet is as below: `my @log_patterns = ( qr/ERROR/, qr/Error/, qr/FATAL/i, qr/critical/i, ); my @log_lines=<$read_tmp_log>; my $i; my $j; for (@log_patterns){ for $i (0..$#log_lines) { next unless $log_lines[$i] =~ $_; my $a = $i - 5 < 0 ? 0 : $i - 5;; my $b = $i + 5 > $#log_lines ? $#log_lines : $i + 5; print $output_file "\n"; for $j($a..$b){ print $output_file $log_lines[$j]; } } }` [download]	[reply] [d/l]
Re^3: Print line from file only once even if occurrence of pattern is more than once in the line by pme (Monsignor) on Mar 29, 2015 at 18:10 UTC
Hi jayu_rao, Try to do this way: `while(<$read_tmp_log>) { # reads input line if ( /error\|fatal\|critical/i ) { # if the line contains error, fata +l or critical case insensitively ... # process data } }` [download]	[reply] [d/l]
Re^4: Print line from file only once even if occurrence of pattern is more than once in the line by jayu_rao (Sexton) on Mar 29, 2015 at 18:22 UTC
Re^5: Print line from file only once even if occurrence of pattern is more than once in the line by pme (Monsignor) on Mar 29, 2015 at 18:40 UTC
Re^4: Print line from file only once even if occurrence of pattern is more than once in the line by jayu_rao (Sexton) on Mar 29, 2015 at 19:18 UTC
Re^5: Print line from file only once even if occurrence of pattern is more than once in the line by Cristoforo (Curate) on Mar 30, 2015 at 02:18 UTC
Re^3: Print line from file only once even if occurrence of pattern is more than once in the line (double?) by LanX (Saint) on Mar 29, 2015 at 18:38 UTC
Ehm...What's the difference to the question you already asked two weeks ago? Print 5 lines before and after pattern match from a list Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :)} PS: Je suis Charlie!	[reply]
Re^4: Print line from file only once even if occurrence of pattern is more than once in the line (double?) by jayu_rao (Sexton) on Mar 29, 2015 at 19:11 UTC
Re: Print line from file only once even if occurrence of pattern is more than once in the line by kcott (Archbishop) on Mar 29, 2015 at 18:02 UTC
G'day jayu_rao, You're going to have to show us some of this code you've written to get any sort of reasonable answer. The problem could be a major design flaw, a typo in a regex, or something else: we don't know. [See guidelines: How do I post a question effectively?] -- Ken	[reply]
Re: Print line from file only once even if occurrence of pattern is more than once in the line by CountZero (Bishop) on Mar 29, 2015 at 17:58 UTC
It would indeed help if at least you show us the regex you are using. CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James My blog: Imperial Deltronics	[reply]
Re: Print line from file only once even if occurrence of pattern is more than once in the line by sandy105 (Scribe) on Mar 30, 2015 at 11:16 UTC
i wrote something similar a while back . `@line = <filehandle> #filehandle used for opening the file foreach my $line (@lines) { #note i am matching a line doing something like printin +g and then using next .. if($line =~/^ProcessName:/){ $mess = substr $keyword , 13; $unirec{$id} .="$date,$id,$mess\n"; next; } if($line =~/^Process Message :/ ){ $mess = substr $keyword , 18; $unirec{$id} .="$date,$id,$mess\n"; next; } }` [download]	[reply] [d/l]