Fear Me Not

This was a lightning talk given by my wife, Dana Gray, at MountainWest RubyConf 2009. She encouraged programmers to shed their fear of regular expressions and learn to use them properly.

Transcript

1. Don’t worry, there are only four. Fear Me Not Tips for Conquering Regular Expressions
2. Contrary to popular opinion, Regex doesn’t have to make you feel like this => Popular Opinion
3. Do I need help?
4. Do I need help? My name is Dana and I like Regular Expressions
5. Do I need help? My name is Dana and I like Regular Expressions It’s been two days since my last Regular Expression
6. When is the end
   really the end?
7. When is the end
   really the end? data[/\d+$/] # => "10"
8. When is the end
   really the end? data[/\d+$/] # => "10" attendance = "Women = 10 Men = 215 Total = 225 "
9. When is the end
   really the end? data[/\d+$/] # => "10" data[/\d+\z/] # => nil attendance = "Women = 10 Men = 215 Total = 225 "
10. When is the end
    really the end? data[/\d+$/] # => "10" data[/\d+\z/] # => nil data[/\d+\Z/] # => "225" attendance = "Women = 10 Men = 215 Total = 225 "
11. In Ruby dummy talk, please
12. In Ruby dummy talk, please Symbol WTF?
13. In Ruby dummy talk, please Symbol WTF? ^ Matches the beginning of any line - 100 lines means 100 matches
14. In Ruby dummy talk, please Symbol WTF? ^ Matches the beginning of any line - 100 lines means 100 matches \A Matches the beginning of the string - at most 1 match
15. In Ruby dummy talk, please Symbol WTF? ^ Matches the beginning of any line - 100 lines means 100 matches \A Matches the beginning of the string - at most 1 match $ Matches the end of any line - 100 lines means 100 matches
16. In Ruby dummy talk, please Symbol WTF? ^ Matches the beginning of any line - 100 lines means 100 matches \A Matches the beginning of the string - at most 1 match $ Matches the end of any line - 100 lines means 100 matches \z Matches the end of the string - at most 1 match
17. In Ruby dummy talk, please Symbol WTF? ^ Matches the beginning of any line - 100 lines means 100 matches \A Matches the beginning of the string - at most 1 match $ Matches the end of any line - 100 lines means 100 matches \z Matches the end of the string - at most 1 match \Z Matches the end of the string or just before the last \n - at most 1 match
18. Getting exactly
    what I want
19. Getting exactly
    what I want ["Gray is a great color.", "I like gray things.", "I’m hung up on a guy named Gray.", "He lives in Castle Grayskull."]
20. Getting exactly
    what I want ["Gray is a great color.", "I like gray things.", "I’m hung up on a guy named Gray.", "He lives in Castle Grayskull."] /(\W|\A)gray(\W|\Z)/i
21. Getting exactly
    what I want ["Gray is a great color.", "I like gray things.", "I’m hung up on a guy named Gray.", "He lives in Castle Grayskull."] /(\W|\A)gray(\W|\Z)/i /\bGray\b/i
22. Getting exactly
    what I want ["Gray is a great color.", "I like gray things.", "I’m hung up on a guy named Gray.", "He lives in Castle Grayskull."] /(\W|\A)gray(\W|\Z)/i /\bGray\b/i ["Gray is a great color.", "I like gray things.", "I’m hung up on a guy named Gray."]
23. Let’s discuss our differences What’s the difference between this - ( ... ) ! ! and this? - (?: ... )
24. Let’s discuss our differences What’s the difference between this - ( ... ) ! ! and this? - (?: ... ) phone = "123-456-7890" phone =~ /\A(\d+)-(\d+)-(\d+)\z/ puts "#{$1}#{$2}#{$3}" ! # >> 1234567890
25. Let’s discuss our differences What’s the difference between this - ( ... ) ! ! and this? - (?: ... ) phone = "123-456-7890" phone =~ /\A(\d+)-(\d+)-(\d+)\z/ puts "#{$1}#{$2}#{$3}" ! # >> 1234567890 name = "James Edward Gray II" name =~ /\A(\w+)(?:\s\w+)?\s(\w+)/ puts "#{$1} #{$2}" ! # >> James Gray
26. When you can’t make up your mind Sometimes you just can’t decide exactly what you want
27. When you can’t make up your mind Sometimes you just can’t decide exactly what you want /(42|41|40|...)/
28. When you can’t make up your mind Sometimes you just can’t decide exactly what you want /(42|41|40|...)/ /[0-9]/
29. When you can’t make up your mind Sometimes you just can’t decide exactly what you want /(42|41|40|...)/ /[0-9]/ /[1-3]?[0-9]/
30. When you can’t make up your mind Sometimes you just can’t decide exactly what you want /(42|41|40|...)/ /[0-9]/ /[1-3]?[0-9]/ /(4[0-2]|[1-3]?[0-9])/
32. "Fear Regex".sub!(/\AFear\b/, "Embrace")