zx81

California, Australia or NZ

My Favorite Question

This is the question I had the most fun answering so far. It's a simple but really effective regex technique that can be used in a surprisingly large number of situations.

Matching or replacing something, except when x, y or z...

Tricks / Answers I had fun with

  • Match Any English ASCII Character Including Special Characters
  • What's in a $? It depends!
  • Matching between Variable Delimiters: Use a Conditional
  • One Set of Parentheses, One Group Number: Branch Reset
  • At which position in the string did the regex fail?
  • Match all possible groups of one to four words
  • [][] and friends: So you thought matching brackets was easy?
  • Match Partially Duplicated lines
  • Refactor a Regex with Subroutines
  • Regex for nested (overlapping) matches
  • Regex Calculators (RPN and non-RPN)
  • Match the last group of (potentially) nested brackets
  • Reverse-engineer regex pattern to find number of tokens and length of expected matches
  • Replace Match with the Number of the Line where it was Found
  • Extract All Unique Lines
  • Matching French letters
  • Capturing Two Optional Groups that Can Occur in Either Order

Answers I loved reading

  • What's a number?
  • Replacing accented characters
  • Options for Forced Failure (ignore the accepted answer). This is just for fun—the standard is (?!) or (*F) in Perl and PCRE.

Work in progress—I really want to add more here. By far the greatest thrill I get on Stack is when I read an answer that makes me go "Aha!..." and grasp a way of doing things that is so much more efficient than anything I had come up with. I've been blown away quite a few times. And one thing that's for sure is there's no shortage here of people who are a lot brighter than me. :)

Top Answers
1 2 3 4