On Wednesday, February 24, 2016 at 12:00:22 PM UTC-6, Paul wrote: > I have a text file and I would like to compose a regular expression > that matches lines containing stringB but not preceded by a line > containing string A. I thought one of these might do it: > > \(stringA.*\n\)\@<!.*stringB > \(stringA.*\n\)\@<!\(.*stringB\) > > The \@<! was *intended* to ensure a non-match with stringA in the > preceding line. However, they highlight the same lines that are > highlighted by the opposite regular expressions: > > \(stringA.*\n\)\@<=.*stringB > \(stringA.*\n\)\@<=\(.*stringB\) > > With a little pondering, it is obvious why. The first .* matches any > set of characters, so even if stringA exists in the preceding line, > you can always find some portion of the line that doesn't match > \(stringA.*\n\). > > Is there a way to achieve the search described in above?
Move the newline outside of your negative look-behind, then start the match using \zs after the newline if you only want to match the 2nd line. Make it work on the 1st line as well by temporarily inserting a blank line at the top, or checking it manually, if needed. Here's what I mean, if my description isn't clear: \(stringA.*\)\@<!\n\zs.*stringB -- -- You received this message from the "vim_use" maillist. Do not top-post! Type your reply below the text you are replying to. For more information, visit http://www.vim.org/maillist.php --- You received this message because you are subscribed to the Google Groups "vim_use" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
