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Regex style and efficiencyby bobf (Monsignor) |
on Jan 10, 2010 at 22:07 UTC ( [id://816649]=perlquestion: print w/replies, xml ) | Need Help?? |
bobf has asked for the wisdom of the Perl Monks concerning the following question: I have a string that begins with a variable sequence of characters, which is followed by a constant string that can be used as a unique anchor. I want to strip off the variable stuff at the beginning so that it begins with the anchor. For example, given this: I want to end with this:
I can think of several ways to approach this, but I do not know which might be considered better than others from the standpoint of style or efficiency (not just benchmarking, but also including potential for backtracking). These approaches include:
All of these employ .* (except for the silly constructs, which are left as an exercise for the reader), but I am trying to avoid that idiom by thinking more carefully about my regexen (Death to Dot Star!). I suspect a better regex might be something like a negated character class, but for a group: "match everything from the start of the string that does not match the sequence of characters anchor". How would you do this, and why?
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