On Tue, Jan 18, 2011 at 01:29:50PM -0600, Christopher Stone wrote: > Hey Folks, > > I've been looking at positive and negative assertions until my head is > spinning. :) > > What I want to do is find the entirety of line 1 but *not* line 2: > > ./Address Book.app > ./Address Book.app/Contents/CodeResources.app > > So I want to find a line that ends with ".app" but it cannot contain ".app" > except at the end. >
Here's the approach I usually take for this kind of task: ^(?>(?:(?!\.app).)*)\.app$ (?:(?!\.app).)* matches a substring that doesn't contain ".app". It does this by checking whether the next part of the string is ".app"; if it's not, it matches one character, and repeats. (?>...) prevents the regex from backtracking into its subexpression once it matches. We know that if the regex doesn't get to the end of the string, backtracking isn't going to help. But I also thought of a simpler approach in this case: ^(?!.*\.app.*\.app).*\.app$ That one uses a negative lookahead to make sure the string doesn't contain .app twice, and then matches if it contains .app at the end of the string. Ronald -- You received this message because you are subscribed to the "BBEdit Talk" discussion group on Google Groups. To post to this group, send email to bbedit@googlegroups.com To unsubscribe from this group, send email to bbedit+unsubscr...@googlegroups.com For more options, visit this group at <http://groups.google.com/group/bbedit?hl=en> If you have a feature request or would like to report a problem, please email "supp...@barebones.com" rather than posting to the group. Follow @bbedit on Twitter: <http://www.twitter.com/bbedit>
