Re^3: How can I print three lines before pattern match?

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Re^4: How can I print three lines before pattern match? by neurotoxx (Novice) on Aug 14, 2009 at 22:37 UTC
What does the '' vs. "\n" do? How could I print also the same line that has the pattern match? Thank you Sifu,<\p> Neurotoxx	[reply]
Re^5: How can I print three lines before pattern match? by ikegami (Patriarch) on Aug 15, 2009 at 02:12 UTC
Print the empty string prints nothing. Printing a newline prints an empty line. `my @history = ('') x 3; while (<>) { print @history, $_ if /pattern/; push @history, $_; shift @history; }` [download] or `my @history = ('') x 4; while (<>) { push @history, $_; shift @history; print @history, $_ if /pattern/; }` [download]	[reply] [d/l] [select]
Re^4: How can I print three lines before pattern match? by neurotoxx (Novice) on Aug 17, 2009 at 01:42 UTC
Thank you very much for your help. I'm sorry to bother, but how can I add the existing matched line with the three lines? `++, but that should be my @history = ('') x 3;` [download] `++, but that should be my @history = ('') x 3 + $.; #???` [download] Thank you agian.	[reply] [d/l] [select]
Re^5: How can I print three lines before pattern match? by ikegami (Patriarch) on Aug 17, 2009 at 02:23 UTC
Already asked. Alread answered	[reply]
Re^5: How can I print three lines before pattern match? by neurotoxx (Novice) on Aug 17, 2009 at 16:43 UTC
Figured it out...to add the line that contains the match string, I added an additional line to the loop. Probably not the best way, but it works. `while (<$_>) { print OUT @history if /$pattern/; print OUT $_ if /$pattern/; # adds line with match push @history, $_; shift @history; }` [download] Thanks again every one, Neurotoxx	[reply] [d/l]
Re^6: How can I print three lines before pattern match? by ikegami (Patriarch) on Aug 17, 2009 at 17:12 UTC
Probably not the best way Indeed. You perform the regex match twice for nothing. The two previously submitted solutions are better. -- for asking for help then ignoring the answers twice.	[reply]